399320865 has 48 divisors (see below), whose sum is σ = 720954000. Its totient is φ = 204212736.

The previous prime is 399320851. The next prime is 399320879. The reversal of 399320865 is 568023993.

It is an interprime number because it is at equal distance from previous prime (399320851) and next prime (399320879).

It can be written as a sum of positive squares in 8 ways, for example, as 576 + 399320289 = 24^2 + 19983^2 .

It is not a de Polignac number, because 399320865 - 2⁸ = 399320609 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 399320865.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 203911 + ... + 205859.

It is an arithmetic number, because the mean of its divisors is an integer number (15019875).

Almost surely, 2^399320865 is an apocalyptic number.

It is an amenable number.

399320865 is a deficient number, since it is larger than the sum of its proper divisors (321633135).

399320865 is a wasteful number, since it uses less digits than its factorization.

399320865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2146 (or 2143 counting only the distinct ones).

The product of its (nonzero) digits is 349920, while the sum is 45.

The square root of 399320865 is about 19983.0144122452. The cubic root of 399320865 is about 736.3890710548.

The spelling of 399320865 in words is "three hundred ninety-nine million, three hundred twenty thousand, eight hundred sixty-five".