391042664 has 8 divisors (see below), whose sum is σ = 733205010. Its totient is φ = 195521328.

The previous prime is 391042657. The next prime is 391042703. The reversal of 391042664 is 466240193.

It can be written as a sum of positive squares in only one way, i.e., 345588100 + 45454564 = 18590^2 + 6742^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 24440159 + ... + 24440174.

Almost surely, 2^391042664 is an apocalyptic number.

It is an amenable number.

391042664 is a deficient number, since it is larger than the sum of its proper divisors (342162346).

391042664 is a wasteful number, since it uses less digits than its factorization.

391042664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 48880339 (or 48880335 counting only the distinct ones).

The product of its (nonzero) digits is 31104, while the sum is 35.

The square root of 391042664 is about 19774.7987094686. The cubic root of 391042664 is about 731.2648765669.

The spelling of 391042664 in words is "three hundred ninety-one million, forty-two thousand, six hundred sixty-four".