640661115036 has 24 divisors (see below), whose sum is σ = 1495071736704. Its totient is φ = 213525733360.

The previous prime is 640661115019. The next prime is 640661115067. The reversal of 640661115036 is 630511166046.

It is a junction number, because it is equal to n+sod(n) for n = 640661114985 and 640661115003.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3400920 + ... + 3584351.

It is an arithmetic number, because the mean of its divisors is an integer number (62294655696).

Almost surely, 2^640661115036 is an apocalyptic number.

It is an amenable number.

640661115036 is an abundant number, since it is smaller than the sum of its proper divisors (854410621668).

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

640661115036 is a wasteful number, since it uses less digits than its factorization.

640661115036 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6992921 (or 6992919 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 39.

The spelling of 640661115036 in words is "six hundred forty billion, six hundred sixty-one million, one hundred fifteen thousand, thirty-six".