3891399979 has 2 divisors, whose sum is σ = 3891399980. Its totient is φ = 3891399978.

The previous prime is 3891399949. The next prime is 3891399989. The reversal of 3891399979 is 9799931983.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 3891399979 - 2⁵ = 3891399947 is a prime.

It is a super-2 number, since 2×3891399979² = 30285987593122400882, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (3891399949) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1945699989 + 1945699990.

It is an arithmetic number, because the mean of its divisors is an integer number (1945699990).

Almost surely, 2^3891399979 is an apocalyptic number.

3891399979 is a deficient number, since it is larger than the sum of its proper divisors (1).

3891399979 is an equidigital number, since it uses as much as digits as its factorization.

3891399979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 29760696, while the sum is 67.

The square root of 3891399979 is about 62381.0867090339. The cubic root of 3891399979 is about 1572.9030602714.

The spelling of 3891399979 in words is "three billion, eight hundred ninety-one million, three hundred ninety-nine thousand, nine hundred seventy-nine".