642564 has 36 divisors (see below), whose sum is σ = 1750476. Its totient is φ = 197568.

The previous prime is 642563. The next prime is 642581. The reversal of 642564 is 465246.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 412164 + 230400 = 642^2 + 480^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 642564.

It is not an unprimeable number, because it can be changed into a prime (642563) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 219 + ... + 1154.

2⁶⁴²⁵⁶⁴ is an apocalyptic number.

It is an amenable number.

642564 is an abundant number, since it is smaller than the sum of its proper divisors (1107912).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

642564 is a wasteful number, since it uses less digits than its factorization.

642564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1396 (or 1391 counting only the distinct ones).

The product of its digits is 5760, while the sum is 27.

The square root of 642564 is about 801.6008982031. The cubic root of 642564 is about 86.2923169787.

Subtracting from 642564 its product of digits (5760), we obtain a square (636804 = 798²).

It can be divided in two parts, 64 and 2564, that added together give a triangular number (2628 = T₇₂).

The spelling of 642564 in words is "six hundred forty-two thousand, five hundred sixty-four".