636860666 has 16 divisors (see below), whose sum is σ = 1036290024. Its totient is φ = 291788544.

The previous prime is 636860663. The next prime is 636860689. The reversal of 636860666 is 666068636.

It can be written as a sum of positive squares in 4 ways, for example, as 511890625 + 124970041 = 22625^2 + 11179^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 636860666.

It is not an unprimeable number, because it can be changed into a prime (636860663) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 85835 + ... + 92958.

Almost surely, 2^636860666 is an apocalyptic number.

636860666 is a deficient number, since it is larger than the sum of its proper divisors (399429358).

636860666 is a wasteful number, since it uses less digits than its factorization.

636860666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 178945.

The product of its (nonzero) digits is 1119744, while the sum is 47.

The square root of 636860666 is about 25236.0984702469. The cubic root of 636860666 is about 860.3625053697.

The spelling of 636860666 in words is "six hundred thirty-six million, eight hundred sixty thousand, six hundred sixty-six".