399740569 has 2 divisors, whose sum is σ = 399740570. Its totient is φ = 399740568.

The previous prime is 399740531. The next prime is 399740573. The reversal of 399740569 is 965047993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 313714944 + 86025625 = 17712^2 + 9275^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-399740569 is a prime.

It is a super-2 number, since 2×399740569² = 319585045008887522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (399740269) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199870284 + 199870285.

It is an arithmetic number, because the mean of its divisors is an integer number (199870285).

Almost surely, 2^399740569 is an apocalyptic number.

It is an amenable number.

399740569 is a deficient number, since it is larger than the sum of its proper divisors (1).

399740569 is an equidigital number, since it uses as much as digits as its factorization.

399740569 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1837080, while the sum is 52.

The square root of 399740569 is about 19993.5131730269. The cubic root of 399740569 is about 736.6469732820.

The spelling of 399740569 in words is "three hundred ninety-nine million, seven hundred forty thousand, five hundred sixty-nine".