399975 has 12 divisors (see below), whose sum is σ = 661416. Its totient is φ = 213280.

The previous prime is 399953. The next prime is 399979. The reversal of 399975 is 579993.

It is a happy number.

It is not a de Polignac number, because 399975 - 2⁶ = 399911 is a prime.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 399975.

It is not an unprimeable number, because it can be changed into a prime (399979) 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, 2592 + ... + 2741.

It is an arithmetic number, because the mean of its divisors is an integer number (55118).

2³⁹⁹⁹⁷⁵ is an apocalyptic number.

399975 is a deficient number, since it is larger than the sum of its proper divisors (261441).

399975 is a wasteful number, since it uses less digits than its factorization.

399975 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5346 (or 5341 counting only the distinct ones).

The product of its digits is 76545, while the sum is 42.

The square root of 399975 is about 632.4357674895. The cubic root of 399975 is about 73.6790949277.

It can be divided in two parts, 3999 and 75, that multiplied together give a triangular number (299925 = T₇₇₄).

The spelling of 399975 in words is "three hundred ninety-nine thousand, nine hundred seventy-five".