391920663 has 8 divisors (see below), whose sum is σ = 522707328. Its totient is φ = 261207224.

The previous prime is 391920653. The next prime is 391920677. The reversal of 391920663 is 366029193.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 391920663 - 2⁸ = 391920407 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (391920653) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4281 + ... + 28322.

It is an arithmetic number, because the mean of its divisors is an integer number (65338416).

Almost surely, 2^391920663 is an apocalyptic number.

391920663 is a deficient number, since it is larger than the sum of its proper divisors (130786665).

391920663 is a wasteful number, since it uses less digits than its factorization.

391920663 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36613.

The product of its (nonzero) digits is 52488, while the sum is 39.

The square root of 391920663 is about 19796.9862100270. The cubic root of 391920663 is about 731.8117648064.

The spelling of 391920663 in words is "three hundred ninety-one million, nine hundred twenty thousand, six hundred sixty-three".