146 is a natural number that follows 145 and precedes 147. In arithmetic it is an even composite integer with a simple prime factorization 2 × 73. Because it is the product of two primes, 146 is a semiprime. Its common numeric representations include binary 10010010, octal 222, hexadecimal 92, and Roman numeral CXLVI.

Basic arithmetic and divisors

The positive divisors of 146 are 1, 2, 73 and 146. The sum of all divisors (the sigma function) equals 222, while the sum of proper divisors is 76, which is less than 146; therefore 146 is a deficient number. The Euler totient function φ(146) = 72, since φ(2×73)=φ(2)×φ(73)=1×72.

Number-theoretic properties

  • Semiprime: 146 = 2 × 73 (an even semiprime of the form 2p where p is prime).
  • Sum of two squares: 146 = 11² + 5², so it can be expressed as a sum of two integer squares.
  • Difference of squares: it cannot be written as a difference of two integer squares because numbers congruent to 2 modulo 4 have no such representation.
  • Deficiency: proper divisors sum to 76 < 146, so it is not perfect or abundant.

The aliquot sequence starting at 146 (repeatedly replacing a number by the sum of its proper divisors) proceeds: 146 → 76 → 64 → 63 → 41 → 1 → 0. Thus the sequence terminates at 0 after reaching the prime 41. This behavior is typical for many semiprimes that eventually fall into small numbers or primes under the aliquot map.

As an elementary integer, 146 appears in diverse basic contexts (coding exercises, examples in number theory texts) but has no widely recognized special status like being a factorial, perfect power, or highly composite number. Its factors and simple representations make it a straightforward illustrative example when discussing semiprimes, sums of squares, and multiplicative arithmetic functions.