640018872860 has 24 divisors (see below), whose sum is σ = 1362451137936. Its totient is φ = 252500595840.

The previous prime is 640018872761. The next prime is 640018872863. The reversal of 640018872860 is 68278810046.

It is a junction number, because it is equal to n+sod(n) for n = 640018872799 and 640018872808.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640018872863) 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, 219183086 + ... + 219186005.

It is an arithmetic number, because the mean of its divisors is an integer number (56768797414).

Almost surely, 2^640018872860 is an apocalyptic number.

It is an amenable number.

640018872860 is an abundant number, since it is smaller than the sum of its proper divisors (722432265076).

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

640018872860 is a wasteful number, since it uses less digits than its factorization.

640018872860 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 438369173 (or 438369171 counting only the distinct ones).

The product of its (nonzero) digits is 1032192, while the sum is 50.

The spelling of 640018872860 in words is "six hundred forty billion, eighteen million, eight hundred seventy-two thousand, eight hundred sixty".