215643664 has 20 divisors (see below), whose sum is σ = 418577004. Its totient is φ = 107623808.

The previous prime is 215643613. The next prime is 215643671. The reversal of 215643664 is 466346512.

It can be written as a sum of positive squares in 2 ways, for example, as 33177600 + 182466064 = 5760^2 + 13508^2 .

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3187 + ... + 21010.

Almost surely, 2^215643664 is an apocalyptic number.

It is an amenable number.

215643664 is a deficient number, since it is larger than the sum of its proper divisors (202933340).

215643664 is a wasteful number, since it uses less digits than its factorization.

215643664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24762 (or 24756 counting only the distinct ones).

The product of its digits is 103680, while the sum is 37.

The square root of 215643664 is about 14684.8106559125. The cubic root of 215643664 is about 599.6698776580.

The spelling of 215643664 in words is "two hundred fifteen million, six hundred forty-three thousand, six hundred sixty-four".