391745664 has 48 divisors (see below), whose sum is σ = 1127292270. Its totient is φ = 130581504.

The previous prime is 391745593. The next prime is 391745687. The reversal of 391745664 is 466547193.

It can be written as a sum of positive squares in only one way, i.e., 256256064 + 135489600 = 16008^2 + 11640^2 .

It is a tau number, because it is divible by the number of its divisors (48).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 168877 + ... + 171180.

Almost surely, 2^391745664 is an apocalyptic number.

It is an amenable number.

391745664 is an abundant number, since it is smaller than the sum of its proper divisors (735546606).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

391745664 is a wasteful number, since it uses less digits than its factorization.

391745664 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 340077 (or 340062 counting only the distinct ones).

The product of its digits is 544320, while the sum is 45.

The square root of 391745664 is about 19792.5658771166. The cubic root of 391745664 is about 731.7028266079.

The spelling of 391745664 in words is "three hundred ninety-one million, seven hundred forty-five thousand, six hundred sixty-four".