391391368691 has 4 divisors (see below), whose sum is σ = 391450686000. Its totient is φ = 391332051384.

The previous prime is 391391368657. The next prime is 391391368721. The reversal of 391391368691 is 196863193193.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 391391368691 - 2¹⁰ = 391391367667 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 391391368691.

It is not an unprimeable number, because it can be changed into a prime (391391368891) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29648756 + ... + 29661953.

It is an arithmetic number, because the mean of its divisors is an integer number (97862671500).

Almost surely, 2^391391368691 is an apocalyptic number.

391391368691 is a deficient number, since it is larger than the sum of its proper divisors (59317309).

391391368691 is an equidigital number, since it uses as much as digits as its factorization.

391391368691 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59317308.

The product of its digits is 5668704, while the sum is 59.

The spelling of 391391368691 in words is "three hundred ninety-one billion, three hundred ninety-one million, three hundred sixty-eight thousand, six hundred ninety-one".