399959009 has 2 divisors, whose sum is σ = 399959010. Its totient is φ = 399959008.

The previous prime is 399959003. The next prime is 399959047. The reversal of 399959009 is 900959993.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 319408384 + 80550625 = 17872^2 + 8975^2 .

It is a cyclic number.

It is not a de Polignac number, because 399959009 - 2²⁰ = 398910433 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (399959003) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199979504 + 199979505.

It is an arithmetic number, because the mean of its divisors is an integer number (199979505).

Almost surely, 2^399959009 is an apocalyptic number.

It is an amenable number.

399959009 is a deficient number, since it is larger than the sum of its proper divisors (1).

399959009 is an equidigital number, since it uses as much as digits as its factorization.

399959009 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 885735, while the sum is 53.

The square root of 399959009 is about 19998.9751987446. The cubic root of 399959009 is about 736.7811301791.

The spelling of 399959009 in words is "three hundred ninety-nine million, nine hundred fifty-nine thousand, nine".