399915 has 12 divisors (see below), whose sum is σ = 693264. Its totient is φ = 213264.

The previous prime is 399913. The next prime is 399937. The reversal of 399915 is 519993.

It is not a de Polignac number, because 399915 - 2¹ = 399913 is a prime.

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 399915.

It is not an unprimeable number, because it can be changed into a prime (399911) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4399 + ... + 4488.

It is an arithmetic number, because the mean of its divisors is an integer number (57772).

2³⁹⁹⁹¹⁵ is an apocalyptic number.

399915 is a deficient number, since it is larger than the sum of its proper divisors (293349).

399915 is a wasteful number, since it uses less digits than its factorization.

399915 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8898 (or 8895 counting only the distinct ones).

The product of its digits is 10935, while the sum is 36.

The square root of 399915 is about 632.3883300631. The cubic root of 399915 is about 73.6754105585.

It can be divided in two parts, 399 and 915, that multiplied together give a triangular number (365085 = T₈₅₄).

The spelling of 399915 in words is "three hundred ninety-nine thousand, nine hundred fifteen".