6659865664 has 35 divisors (see below), whose sum is σ = 13347827635. Its totient is φ = 3296963200.

The previous prime is 6659865647. The next prime is 6659865683. The reversal of 6659865664 is 4665689566.

It is a happy number.

The square root of 6659865664 is 81608.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 2 ways, for example, as 5656243264 + 1003622400 = 75208^2 + 31680^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=4, B=202.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 4 ways as a sum of consecutive naturals, for example, 65939214 + ... + 65939314.

Almost surely, 2^6659865664 is an apocalyptic number.

6659865664 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

6659865664 is the 81608-th square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6659865664

6659865664 is an abundant number, since it is smaller than the sum of its proper divisors (6687961971).

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

6659865664 is an frugal number, since it uses more digits than its factorization.

6659865664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 416 (or 103 counting only the distinct ones).

The product of its digits is 55987200, while the sum is 61.

The cubic root of 6659865664 is about 1881.4318411527.

The spelling of 6659865664 in words is "six billion, six hundred fifty-nine million, eight hundred sixty-five thousand, six hundred sixty-four".