399715 has 4 divisors (see below), whose sum is σ = 479664. Its totient is φ = 319768.

The previous prime is 399691. The next prime is 399719. The reversal of 399715 is 517993.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 517993 = 7 ⋅73999.

It is a cyclic number.

It is not a de Polignac number, because 399715 - 2⁷ = 399587 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399719) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39967 + ... + 39976.

It is an arithmetic number, because the mean of its divisors is an integer number (119916).

2³⁹⁹⁷¹⁵ is an apocalyptic number.

399715 is a deficient number, since it is larger than the sum of its proper divisors (79949).

399715 is an equidigital number, since it uses as much as digits as its factorization.

399715 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79948.

The product of its digits is 8505, while the sum is 34.

The square root of 399715 is about 632.2301796023. The cubic root of 399715 is about 73.6631266655.

It can be divided in two parts, 39 and 9715, that multiplied together give a triangular number (378885 = T₈₇₀).

The spelling of 399715 in words is "three hundred ninety-nine thousand, seven hundred fifteen".