640005936 has 40 divisors (see below), whose sum is σ = 1750606704. Its totient is φ = 200785920.

The previous prime is 640005931. The next prime is 640005991. The reversal of 640005936 is 639500046.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 640005897 and 640005906.

It is not an unprimeable number, because it can be changed into a prime (640005931) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 391345 + ... + 392976.

Almost surely, 2^640005936 is an apocalyptic number.

It is an amenable number.

640005936 is an abundant number, since it is smaller than the sum of its proper divisors (1110600768).

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

640005936 is a wasteful number, since it uses less digits than its factorization.

640005936 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 784349 (or 784343 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 33.

The square root of 640005936 is about 25298.3386015762. The cubic root of 640005936 is about 861.7765403221.

The spelling of 640005936 in words is "six hundred forty million, five thousand, nine hundred thirty-six".