399724 has 12 divisors (see below), whose sum is σ = 753424. Its totient is φ = 184464.

The previous prime is 399719. The next prime is 399727. The reversal of 399724 is 427993.

399724 is nontrivially palindromic in base 14.

It is a hoax number, since the sum of its digits (34) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 399724.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399727) 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, 3792 + ... + 3895.

2³⁹⁹⁷²⁴ is an apocalyptic number.

It is an amenable number.

399724 is a deficient number, since it is larger than the sum of its proper divisors (353700).

399724 is a wasteful number, since it uses less digits than its factorization.

399724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7704 (or 7702 counting only the distinct ones).

The product of its digits is 13608, while the sum is 34.

The square root of 399724 is about 632.2372972231. The cubic root of 399724 is about 73.6636795287.

The spelling of 399724 in words is "three hundred ninety-nine thousand, seven hundred twenty-four".