6639469864 has 8 divisors (see below), whose sum is σ = 12449006010. Its totient is φ = 3319734928.

The previous prime is 6639469861. The next prime is 6639469883. The reversal of 6639469864 is 4689649366.

It can be written as a sum of positive squares in only one way, i.e., 6430436100 + 209033764 = 80190^2 + 14458^2 .

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

It is not an unprimeable number, because it can be changed into a prime (6639469861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 414966859 + ... + 414966874.

Almost surely, 2^6639469864 is an apocalyptic number.

It is an amenable number.

6639469864 is a deficient number, since it is larger than the sum of its proper divisors (5809536146).

6639469864 is a wasteful number, since it uses less digits than its factorization.

6639469864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 829933739 (or 829933735 counting only the distinct ones).

The product of its digits is 40310784, while the sum is 61.

The square root of 6639469864 is about 81482.9421658300. The cubic root of 6639469864 is about 1879.5092524728.

The spelling of 6639469864 in words is "six billion, six hundred thirty-nine million, four hundred sixty-nine thousand, eight hundred sixty-four".