660405388 has 12 divisors (see below), whose sum is σ = 1156414392. Its totient is φ = 330001280.

The previous prime is 660405331. The next prime is 660405397. The reversal of 660405388 is 883504066.

It is a super-2 number, since 2×660405388² = 872270552998861088, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 660405388.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42853 + ... + 56188.

It is an arithmetic number, because the mean of its divisors is an integer number (96367866).

Almost surely, 2^660405388 is an apocalyptic number.

It is an amenable number.

660405388 is a deficient number, since it is larger than the sum of its proper divisors (496009004).

660405388 is a wasteful number, since it uses less digits than its factorization.

660405388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 100712 (or 100710 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 40.

The square root of 660405388 is about 25698.3537994168. The cubic root of 660405388 is about 870.8369925402.

The spelling of 660405388 in words is "six hundred sixty million, four hundred five thousand, three hundred eighty-eight".