665156564 has 12 divisors (see below), whose sum is σ = 1165468500. Its totient is φ = 332165568.

The previous prime is 665156563. The next prime is 665156599. The reversal of 665156564 is 465651566.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 291043600 + 374112964 = 17060^2 + 19342^2 .

It is a hoax number, since the sum of its digits (44) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (665156563) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 99539 + ... + 106010.

It is an arithmetic number, because the mean of its divisors is an integer number (97122375).

Almost surely, 2^665156564 is an apocalyptic number.

It is an amenable number.

665156564 is a deficient number, since it is larger than the sum of its proper divisors (500311936).

665156564 is a wasteful number, since it uses less digits than its factorization.

665156564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206362 (or 206360 counting only the distinct ones).

The product of its digits is 648000, while the sum is 44.

The square root of 665156564 is about 25790.6293835571. The cubic root of 665156564 is about 872.9203679835.

The spelling of 665156564 in words is "six hundred sixty-five million, one hundred fifty-six thousand, five hundred sixty-four".