660391388 has 12 divisors (see below), whose sum is σ = 1192965312. Its totient is φ = 319544160.

The previous prime is 660391373. The next prime is 660391427. The reversal of 660391388 is 883193066.

It is a super-2 number, since 2×660391388² = 872233570689133088, which contains 22 as substring.

It is a congruent number.

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, 2662745 + ... + 2662992.

It is an arithmetic number, because the mean of its divisors is an integer number (99413776).

Almost surely, 2^660391388 is an apocalyptic number.

It is an amenable number.

660391388 is a deficient number, since it is larger than the sum of its proper divisors (532573924).

660391388 is a wasteful number, since it uses less digits than its factorization.

660391388 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5325772 (or 5325770 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 44.

The square root of 660391388 is about 25698.0814069845. The cubic root of 660391388 is about 870.8308388432.

The spelling of 660391388 in words is "six hundred sixty million, three hundred ninety-one thousand, three hundred eighty-eight".