642915756 has 72 divisors (see below), whose sum is σ = 1865660160. Its totient is φ = 182864736.

The previous prime is 642915733. The next prime is 642915857. The reversal of 642915756 is 657519246.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 51585 + ... + 62823.

Almost surely, 2^642915756 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 642915756, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (932830080).

642915756 is an abundant number, since it is smaller than the sum of its proper divisors (1222744404).

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

642915756 is a wasteful number, since it uses less digits than its factorization.

642915756 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11483 (or 11478 counting only the distinct ones).

The product of its digits is 453600, while the sum is 45.

The square root of 642915756 is about 25355.7834822748. The cubic root of 642915756 is about 863.0806031486.

The spelling of 642915756 in words is "six hundred forty-two million, nine hundred fifteen thousand, seven hundred fifty-six".