640621662144 has 28 divisors (see below), whose sum is σ = 1694978148264. Its totient is φ = 213540553984.

The previous prime is 640621662133. The next prime is 640621662193. The reversal of 640621662144 is 441266126046.

It is a super-2 number, since 2×640621662144² (a number of 24 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 640621662096 and 640621662105.

It is a congruent number.

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, 1668285387 + ... + 1668285770.

Almost surely, 2^640621662144 is an apocalyptic number.

640621662144 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

It is an amenable number.

640621662144 is an abundant number, since it is smaller than the sum of its proper divisors (1054356486120).

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

640621662144 is a wasteful number, since it uses less digits than its factorization.

640621662144 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3336571172 (or 3336571162 counting only the distinct ones).

The product of its (nonzero) digits is 331776, while the sum is 42.

The spelling of 640621662144 in words is "six hundred forty billion, six hundred twenty-one million, six hundred sixty-two thousand, one hundred forty-four".