399912979 has 2 divisors, whose sum is σ = 399912980. Its totient is φ = 399912978.

The previous prime is 399912941. The next prime is 399912991. The reversal of 399912979 is 979219993.

It is a strong prime.

It is an emirp because it is prime and its reverse (979219993) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 399912979 - 2⁹ = 399912467 is a prime.

It is not a weakly prime, because it can be changed into another prime (399913979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199956489 + 199956490.

It is an arithmetic number, because the mean of its divisors is an integer number (199956490).

Almost surely, 2^399912979 is an apocalyptic number.

399912979 is a deficient number, since it is larger than the sum of its proper divisors (1).

399912979 is an equidigital number, since it uses as much as digits as its factorization.

399912979 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2480058, while the sum is 58.

The square root of 399912979 is about 19997.8243566644. The cubic root of 399912979 is about 736.7528645021.

The spelling of 399912979 in words is "three hundred ninety-nine million, nine hundred twelve thousand, nine hundred seventy-nine".