642956 has 6 divisors (see below), whose sum is σ = 1125180. Its totient is φ = 321476.

The previous prime is 642953. The next prime is 642973. The reversal of 642956 is 659246.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 642956.

It is not an unprimeable number, because it can be changed into a prime (642953) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80366 + ... + 80373.

It is an arithmetic number, because the mean of its divisors is an integer number (187530).

2⁶⁴²⁹⁵⁶ is an apocalyptic number.

It is an amenable number.

642956 is a deficient number, since it is larger than the sum of its proper divisors (482224).

642956 is a wasteful number, since it uses less digits than its factorization.

642956 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160743 (or 160741 counting only the distinct ones).

The product of its digits is 12960, while the sum is 32.

The square root of 642956 is about 801.8453716272. The cubic root of 642956 is about 86.3098611258.

Subtracting 642956 from its reverse (659246), we obtain a triangular number (16290 = T₁₈₀).

The spelling of 642956 in words is "six hundred forty-two thousand, nine hundred fifty-six".