665655556 has 12 divisors (see below), whose sum is σ = 1165253068. Its totient is φ = 332726112.

The previous prime is 665655539. The next prime is 665655559. The reversal of 665655556 is 655556566.

It can be written as a sum of positive squares in 2 ways, for example, as 614246656 + 51408900 = 24784^2 + 7170^2 .

It is not an unprimeable number, because it can be changed into a prime (665655559) 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 in 3 ways as a sum of consecutive naturals, for example, 9591 + ... + 37726.

Almost surely, 2^665655556 is an apocalyptic number.

It is an amenable number.

665655556 is a deficient number, since it is larger than the sum of its proper divisors (499597512).

665655556 is a wasteful number, since it uses less digits than its factorization.

665655556 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50838 (or 50836 counting only the distinct ones).

The product of its digits is 4050000, while the sum is 49.

The square root of 665655556 is about 25800.3014711069. The cubic root of 665655556 is about 873.1385980098.

The spelling of 665655556 in words is "six hundred sixty-five million, six hundred fifty-five thousand, five hundred fifty-six".