664855988 has 12 divisors (see below), whose sum is σ = 1176571620. Its totient is φ = 328692672.

The previous prime is 664855957. The next prime is 664856011. The reversal of 664855988 is 889558466.

664855988 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 407959204 + 256896784 = 20198^2 + 16028^2 .

It is a super-2 number, since 2×664855988² = 884066969558912288, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 933431 + ... + 934142.

It is an arithmetic number, because the mean of its divisors is an integer number (98047635).

Almost surely, 2^664855988 is an apocalyptic number.

It is an amenable number.

664855988 is a deficient number, since it is larger than the sum of its proper divisors (511715632).

664855988 is a wasteful number, since it uses less digits than its factorization.

664855988 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1867666 (or 1867664 counting only the distinct ones).

The product of its digits is 16588800, while the sum is 59.

The square root of 664855988 is about 25784.8014923520. The cubic root of 664855988 is about 872.7888608775.

The spelling of 664855988 in words is "six hundred sixty-four million, eight hundred fifty-five thousand, nine hundred eighty-eight".