399905931 has 8 divisors (see below), whose sum is σ = 533998224. Its totient is φ = 266208800.

The previous prime is 399905929. The next prime is 399905951. The reversal of 399905931 is 139509993.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 399905931 - 2¹ = 399905929 is a prime.

It is a super-2 number, since 2×399905931² = 319849507297953522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (399905951) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 96420 + ... + 100481.

It is an arithmetic number, because the mean of its divisors is an integer number (66749778).

Almost surely, 2^399905931 is an apocalyptic number.

399905931 is a deficient number, since it is larger than the sum of its proper divisors (134092293).

399905931 is a wasteful number, since it uses less digits than its factorization.

399905931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 197581.

The product of its (nonzero) digits is 295245, while the sum is 48.

The square root of 399905931 is about 19997.6481367185. The cubic root of 399905931 is about 736.7485363399.

The spelling of 399905931 in words is "three hundred ninety-nine million, nine hundred five thousand, nine hundred thirty-one".