399263609 has 2 divisors, whose sum is σ = 399263610. Its totient is φ = 399263608.

The previous prime is 399263603. The next prime is 399263611. The reversal of 399263609 is 906362993.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 203347600 + 195916009 = 14260^2 + 13997^2 .

It is a cyclic number.

It is not a de Polignac number, because 399263609 - 2¹⁶ = 399198073 is a prime.

It is a super-2 number, since 2×399263609² = 318822858943409762, which contains 22 as substring.

Together with 399263611, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (399263603) 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, 199631804 + 199631805.

It is an arithmetic number, because the mean of its divisors is an integer number (199631805).

Almost surely, 2^399263609 is an apocalyptic number.

It is an amenable number.

399263609 is a deficient number, since it is larger than the sum of its proper divisors (1).

399263609 is an equidigital number, since it uses as much as digits as its factorization.

399263609 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 472392, while the sum is 47.

The square root of 399263609 is about 19981.5817441963. The cubic root of 399263609 is about 736.3538740393.

The spelling of 399263609 in words is "three hundred ninety-nine million, two hundred sixty-three thousand, six hundred nine".