665559172 has 6 divisors (see below), whose sum is σ = 1164728558. Its totient is φ = 332779584.

The previous prime is 665559157. The next prime is 665559179. The reversal of 665559172 is 271955566.

It can be written as a sum of positive squares in only one way, i.e., 640798596 + 24760576 = 25314^2 + 4976^2 .

It is a super-2 number, since 2×665559172² = 885938022866651168, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (665559179) by changing a digit.

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 as a sum of consecutive naturals, namely, 83194893 + ... + 83194900.

Almost surely, 2^665559172 is an apocalyptic number.

It is an amenable number.

665559172 is a deficient number, since it is larger than the sum of its proper divisors (499169386).

665559172 is a wasteful number, since it uses less digits than its factorization.

665559172 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166389797 (or 166389795 counting only the distinct ones).

The product of its digits is 567000, while the sum is 46.

The square root of 665559172 is about 25798.4335183360. The cubic root of 665559172 is about 873.0964537647.

The spelling of 665559172 in words is "six hundred sixty-five million, five hundred fifty-nine thousand, one hundred seventy-two".