391317919 has 2 divisors, whose sum is σ = 391317920. Its totient is φ = 391317918.

The previous prime is 391317853. The next prime is 391317937. The reversal of 391317919 is 919713193.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 391317919 - 2¹⁵ = 391285151 is a prime.

It is a super-2 number, since 2×391317919² = 306259427460981122, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (391317019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 195658959 + 195658960.

It is an arithmetic number, because the mean of its divisors is an integer number (195658960).

Almost surely, 2^391317919 is an apocalyptic number.

391317919 is a deficient number, since it is larger than the sum of its proper divisors (1).

391317919 is an equidigital number, since it uses as much as digits as its factorization.

391317919 is an evil number, because the sum of its binary digits is even.

The product of its digits is 45927, while the sum is 43.

The square root of 391317919 is about 19781.7572273042. The cubic root of 391317919 is about 731.4364154828.

The spelling of 391317919 in words is "three hundred ninety-one million, three hundred seventeen thousand, nine hundred nineteen".