640692536 has 32 divisors (see below), whose sum is σ = 1316271600. Its totient is φ = 289943040.

The previous prime is 640692523. The next prime is 640692539. The reversal of 640692536 is 635296046.

It is a super-2 number, since 2×640692536² = 820973851372222592, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 640692493 and 640692502.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640692539) 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 in 7 ways as a sum of consecutive naturals, for example, 4256 + ... + 36048.

Almost surely, 2^640692536 is an apocalyptic number.

It is an amenable number.

640692536 is an abundant number, since it is smaller than the sum of its proper divisors (675579064).

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

640692536 is a wasteful number, since it uses less digits than its factorization.

640692536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32039 (or 32035 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 41.

The square root of 640692536 is about 25311.9050251063. The cubic root of 640692536 is about 862.0846022084.

The spelling of 640692536 in words is "six hundred forty million, six hundred ninety-two thousand, five hundred thirty-six".