666718772 has 12 divisors (see below), whose sum is σ = 1167388740. Its totient is φ = 333179136.

The previous prime is 666718763. The next prime is 666718783. The reversal of 666718772 is 277817666.

It can be written as a sum of positive squares in 2 ways, for example, as 297079696 + 369639076 = 17236^2 + 19226^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 666718772.

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, 36563 + ... + 51674.

It is an arithmetic number, because the mean of its divisors is an integer number (97282395).

Almost surely, 2^666718772 is an apocalyptic number.

It is an amenable number.

666718772 is a deficient number, since it is larger than the sum of its proper divisors (500669968).

666718772 is a wasteful number, since it uses less digits than its factorization.

666718772 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 90130 (or 90128 counting only the distinct ones).

The product of its digits is 1185408, while the sum is 50.

The square root of 666718772 is about 25820.8979704425. The cubic root of 666718772 is about 873.6032232440.

The spelling of 666718772 in words is "six hundred sixty-six million, seven hundred eighteen thousand, seven hundred seventy-two".