399000031 has 4 divisors (see below), whose sum is σ = 399171672. Its totient is φ = 398828392.

The previous prime is 399000029. The next prime is 399000037. The reversal of 399000031 is 130000993.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 399000031 - 2¹ = 399000029 is a prime.

It is a super-2 number, since 2×399000031² = 318402049476001922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399000037) 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, 82285 + ... + 86998.

It is an arithmetic number, because the mean of its divisors is an integer number (99792918).

Almost surely, 2^399000031 is an apocalyptic number.

399000031 is a deficient number, since it is larger than the sum of its proper divisors (171641).

399000031 is a wasteful number, since it uses less digits than its factorization.

399000031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 171640.

The product of its (nonzero) digits is 729, while the sum is 25.

The square root of 399000031 is about 19974.9851314087. The cubic root of 399000031 is about 736.1918011614.

The spelling of 399000031 in words is "three hundred ninety-nine million, thirty-one", and thus it is an aban number.