664688880 has 60 divisors (see below), whose sum is σ = 2232249240. Its totient is φ = 177250176.

The previous prime is 664688873. The next prime is 664688881. The reversal of 664688880 is 88886466.

664688880 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (60).

It is a super-2 number, since 2×664688880² = 883622614391308800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664688881) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 460870 + ... + 462309.

It is an arithmetic number, because the mean of its divisors is an integer number (37204154).

Almost surely, 2^664688880 is an apocalyptic number.

664688880 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

664688880 is an abundant number, since it is smaller than the sum of its proper divisors (1567560360).

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

664688880 is a wasteful number, since it uses less digits than its factorization.

664688880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 923198 (or 923189 counting only the distinct ones).

The product of its (nonzero) digits is 3538944, while the sum is 54.

The square root of 664688880 is about 25781.5608526714. The cubic root of 664688880 is about 872.7157311447.

The spelling of 664688880 in words is "six hundred sixty-four million, six hundred eighty-eight thousand, eight hundred eighty".