391616779 has 2 divisors, whose sum is σ = 391616780. Its totient is φ = 391616778.

The previous prime is 391616761. The next prime is 391616801. The reversal of 391616779 is 977616193.

It is a weak prime.

It is an emirp because it is prime and its reverse (977616193) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 391616779 - 2¹¹ = 391614731 is a prime.

It is not a weakly prime, because it can be changed into another prime (391616479) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195808389 + 195808390.

It is an arithmetic number, because the mean of its divisors is an integer number (195808390).

Almost surely, 2^391616779 is an apocalyptic number.

391616779 is a deficient number, since it is larger than the sum of its proper divisors (1).

391616779 is an equidigital number, since it uses as much as digits as its factorization.

391616779 is an evil number, because the sum of its binary digits is even.

The product of its digits is 428652, while the sum is 49.

The square root of 391616779 is about 19789.3097150962. The cubic root of 391616779 is about 731.6225739750.

The spelling of 391616779 in words is "three hundred ninety-one million, six hundred sixteen thousand, seven hundred seventy-nine".