666518056 has 8 divisors (see below), whose sum is σ = 1249721370. Its totient is φ = 333259024.

The previous prime is 666518053. The next prime is 666518113. The reversal of 666518056 is 650815666.

It can be written as a sum of positive squares in only one way, i.e., 558565956 + 107952100 = 23634^2 + 10390^2 .

It is a tau number, because it is divible by the number of its divisors (8).

It is not an unprimeable number, because it can be changed into a prime (666518051) 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, 41657371 + ... + 41657386.

Almost surely, 2^666518056 is an apocalyptic number.

It is an amenable number.

666518056 is a deficient number, since it is larger than the sum of its proper divisors (583203314).

666518056 is a wasteful number, since it uses less digits than its factorization.

666518056 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83314763 (or 83314759 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 43.

The square root of 666518056 is about 25817.0109811341. The cubic root of 666518056 is about 873.5155482248.

The spelling of 666518056 in words is "six hundred sixty-six million, five hundred eighteen thousand, fifty-six".