399660979 has 2 divisors, whose sum is σ = 399660980. Its totient is φ = 399660978.

The previous prime is 399660941. The next prime is 399661027. The reversal of 399660979 is 979066993.

It is a weak prime.

It is an emirp because it is prime and its reverse (979066993) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-399660979 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (399660929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199830489 + 199830490.

It is an arithmetic number, because the mean of its divisors is an integer number (199830490).

Almost surely, 2^399660979 is an apocalyptic number.

399660979 is a deficient number, since it is larger than the sum of its proper divisors (1).

399660979 is an equidigital number, since it uses as much as digits as its factorization.

399660979 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4960116, while the sum is 58.

The square root of 399660979 is about 19991.5226783755. The cubic root of 399660979 is about 736.5980802176.

The spelling of 399660979 in words is "three hundred ninety-nine million, six hundred sixty thousand, nine hundred seventy-nine".