640461217880 has 32 divisors (see below), whose sum is σ = 1572041172240. Its totient is φ = 232894988160.

The previous prime is 640461217853. The next prime is 640461217889. The reversal of 640461217880 is 88712164046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640461217889) 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, 727796399 + ... + 727797278.

Almost surely, 2^640461217880 is an apocalyptic number.

It is an amenable number.

640461217880 is an abundant number, since it is smaller than the sum of its proper divisors (931579954360).

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

640461217880 is a wasteful number, since it uses less digits than its factorization.

640461217880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1455593699 (or 1455593695 counting only the distinct ones).

The product of its (nonzero) digits is 516096, while the sum is 47.

The spelling of 640461217880 in words is "six hundred forty billion, four hundred sixty-one million, two hundred seventeen thousand, eight hundred eighty".