640416880 has 20 divisors (see below), whose sum is σ = 1488969432. Its totient is φ = 256166720.

The previous prime is 640416871. The next prime is 640416883. The reversal of 640416880 is 88614046.

It is a tau number, because it is divible by the number of its divisors (20).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640416883) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4002526 + ... + 4002685.

Almost surely, 2^640416880 is an apocalyptic number.

It is an amenable number.

640416880 is an abundant number, since it is smaller than the sum of its proper divisors (848552552).

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

640416880 is a wasteful number, since it uses less digits than its factorization.

640416880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8005224 (or 8005218 counting only the distinct ones).

The product of its (nonzero) digits is 36864, while the sum is 37.

The square root of 640416880 is about 25306.4592545065. The cubic root of 640416880 is about 861.9609480534.

The spelling of 640416880 in words is "six hundred forty million, four hundred sixteen thousand, eight hundred eighty".