665181656 has 16 divisors (see below), whose sum is σ = 1258659600. Its totient is φ = 329539104.

The previous prime is 665181623. The next prime is 665181667. The reversal of 665181656 is 656181566.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 380540 + ... + 382283.

It is an arithmetic number, because the mean of its divisors is an integer number (78666225).

Almost surely, 2^665181656 is an apocalyptic number.

It is an amenable number.

665181656 is a deficient number, since it is larger than the sum of its proper divisors (593477944).

665181656 is a wasteful number, since it uses less digits than its factorization.

665181656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 762938 (or 762934 counting only the distinct ones).

The product of its digits is 259200, while the sum is 44.

The square root of 665181656 is about 25791.1158347211. The cubic root of 665181656 is about 872.9313443680.

The spelling of 665181656 in words is "six hundred sixty-five million, one hundred eighty-one thousand, six hundred fifty-six".