6620664864 has 48 divisors (see below), whose sum is σ = 18959179680. Its totient is φ = 2006261760.

The previous prime is 6620664857. The next prime is 6620664929. The reversal of 6620664864 is 4684660266.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (48).

It is a Harshad number since it is a multiple of its sum of digits (48).

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3133729 + ... + 3135840.

It is an arithmetic number, because the mean of its divisors is an integer number (394982910).

Almost surely, 2^6620664864 is an apocalyptic number.

It is an amenable number.

6620664864 is an abundant number, since it is smaller than the sum of its proper divisors (12338514816).

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

6620664864 is a wasteful number, since it uses less digits than its factorization.

6620664864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6269593 (or 6269585 counting only the distinct ones).

The product of its (nonzero) digits is 1990656, while the sum is 48.

The square root of 6620664864 is about 81367.4680938273. The cubic root of 6620664864 is about 1877.7331271040.

The spelling of 6620664864 in words is "six billion, six hundred twenty million, six hundred sixty-four thousand, eight hundred sixty-four".