399942 has 24 divisors (see below), whose sum is σ = 918216. Its totient is φ = 125376.

The previous prime is 399941. The next prime is 399953. The reversal of 399942 is 249993.

It is a d-powerful number, because it can be written as 3 + 9² + 9² + 9⁴ + 4⁹ + 2¹⁷ .

It is a junction number, because it is equal to n+sod(n) for n = 399897 and 399906.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399941) 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, 348 + ... + 959.

It is an arithmetic number, because the mean of its divisors is an integer number (38259).

2³⁹⁹⁹⁴² is an apocalyptic number.

399942 is an abundant number, since it is smaller than the sum of its proper divisors (518274).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

399942 is a wasteful number, since it uses less digits than its factorization.

399942 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1332 (or 1329 counting only the distinct ones).

The product of its digits is 17496, while the sum is 36.

The square root of 399942 is about 632.4096773453. The cubic root of 399942 is about 73.6770685702.

The spelling of 399942 in words is "three hundred ninety-nine thousand, nine hundred forty-two".