642491536 has 20 divisors (see below), whose sum is σ = 1310345200. Its totient is φ = 304337952.

The previous prime is 642491527. The next prime is 642491639. The reversal of 642491536 is 635194246.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1056426 + ... + 1057033.

It is an arithmetic number, because the mean of its divisors is an integer number (65517260).

Almost surely, 2^642491536 is an apocalyptic number.

It is an amenable number.

642491536 is an abundant number, since it is smaller than the sum of its proper divisors (667853664).

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

642491536 is a wasteful number, since it uses less digits than its factorization.

642491536 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2113486 (or 2113480 counting only the distinct ones).

The product of its digits is 155520, while the sum is 40.

The square root of 642491536 is about 25347.4167520085. The cubic root of 642491536 is about 862.8907303647.

The spelling of 642491536 in words is "six hundred forty-two million, four hundred ninety-one thousand, five hundred thirty-six".