642556 has 6 divisors (see below), whose sum is σ = 1124480. Its totient is φ = 321276.

The previous prime is 642547. The next prime is 642557. The reversal of 642556 is 655246.

642556 = T₆₅₃ + T₆₅₄ + T₆₅₅.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (642557) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80316 + ... + 80323.

2⁶⁴²⁵⁵⁶ is an apocalyptic number.

642556 is the 655-th centered triangular number.

It is an amenable number.

642556 is a deficient number, since it is larger than the sum of its proper divisors (481924).

642556 is a wasteful number, since it uses less digits than its factorization.

642556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160643 (or 160641 counting only the distinct ones).

The product of its digits is 7200, while the sum is 28.

The square root of 642556 is about 801.5959081732. The cubic root of 642556 is about 86.2919588606.

It can be divided in two parts, 64255 and 6, that added together give a triangular number (64261 = T₃₅₈).

The spelling of 642556 in words is "six hundred forty-two thousand, five hundred fifty-six".