6620478664 has 8 divisors (see below), whose sum is σ = 12413397510. Its totient is φ = 3310239328.

The previous prime is 6620478619. The next prime is 6620478671. The reversal of 6620478664 is 4668740266.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 6604812900 + 15665764 = 81270^2 + 3958^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 413779909 + ... + 413779924.

Almost surely, 2^6620478664 is an apocalyptic number.

It is an amenable number.

6620478664 is a deficient number, since it is larger than the sum of its proper divisors (5792918846).

6620478664 is a wasteful number, since it uses less digits than its factorization.

6620478664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 827559839 (or 827559835 counting only the distinct ones).

The product of its (nonzero) digits is 2322432, while the sum is 49.

The square root of 6620478664 is about 81366.3238938567. The cubic root of 6620478664 is about 1877.7155237770.

The spelling of 6620478664 in words is "six billion, six hundred twenty million, four hundred seventy-eight thousand, six hundred sixty-four".