666635636 has 6 divisors (see below), whose sum is σ = 1166612370. Its totient is φ = 333317816.

The previous prime is 666635621. The next prime is 666635663. The reversal of 666635636 is 636536666.

It can be written as a sum of positive squares in only one way, i.e., 407232400 + 259403236 = 20180^2 + 16106^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 83329451 + ... + 83329458.

It is an arithmetic number, because the mean of its divisors is an integer number (194435395).

Almost surely, 2^666635636 is an apocalyptic number.

It is an amenable number.

666635636 is a deficient number, since it is larger than the sum of its proper divisors (499976734).

666635636 is a wasteful number, since it uses less digits than its factorization.

666635636 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 166658913 (or 166658911 counting only the distinct ones).

The product of its digits is 2099520, while the sum is 47.

The square root of 666635636 is about 25819.2880614474. The cubic root of 666635636 is about 873.5669106339.

The spelling of 666635636 in words is "six hundred sixty-six million, six hundred thirty-five thousand, six hundred thirty-six".