640255616 has 256 divisors, whose sum is σ = 1809561600. Its totient is φ = 217313280.

The previous prime is 640255607. The next prime is 640255621. The reversal of 640255616 is 616552046.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2434301 + ... + 2434563.

It is an arithmetic number, because the mean of its divisors is an integer number (7068600).

Almost surely, 2^640255616 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 640255616, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (904780800).

640255616 is an abundant number, since it is smaller than the sum of its proper divisors (1169305984).

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

640255616 is a wasteful number, since it uses less digits than its factorization.

640255616 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 327 (or 315 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 35.

The square root of 640255616 is about 25303.2728317900. The cubic root of 640255616 is about 861.8885915703. Note that the first 3 decimals are identical.

The spelling of 640255616 in words is "six hundred forty million, two hundred fifty-five thousand, six hundred sixteen".