399359969 has 2 divisors, whose sum is σ = 399359970. Its totient is φ = 399359968.

The previous prime is 399359951. The next prime is 399360007. The reversal of 399359969 is 969953993.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 364313569 + 35046400 = 19087^2 + 5920^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-399359969 is a prime.

It is a super-2 number, since 2×399359969² = 318976769679361922, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (399359069) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199679984 + 199679985.

It is an arithmetic number, because the mean of its divisors is an integer number (199679985).

Almost surely, 2^399359969 is an apocalyptic number.

It is an amenable number.

399359969 is a deficient number, since it is larger than the sum of its proper divisors (1).

399359969 is an equidigital number, since it uses as much as digits as its factorization.

399359969 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15943230, while the sum is 62.

The square root of 399359969 is about 19983.9928192541. The cubic root of 399359969 is about 736.4131075468.

The spelling of 399359969 in words is "three hundred ninety-nine million, three hundred fifty-nine thousand, nine hundred sixty-nine".