399226831 has 2 divisors, whose sum is σ = 399226832. Its totient is φ = 399226830.

The previous prime is 399226829. The next prime is 399226837. The reversal of 399226831 is 138622993.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 399226831 - 2¹ = 399226829 is a prime.

It is a super-2 number, since 2×399226831² = 318764125180605122, which contains 22 as substring.

Together with 399226829, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (399226837) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199613415 + 199613416.

It is an arithmetic number, because the mean of its divisors is an integer number (199613416).

Almost surely, 2^399226831 is an apocalyptic number.

399226831 is a deficient number, since it is larger than the sum of its proper divisors (1).

399226831 is an equidigital number, since it uses as much as digits as its factorization.

399226831 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 139968, while the sum is 43.

The square root of 399226831 is about 19980.6614254884. The cubic root of 399226831 is about 736.3312637022.

The spelling of 399226831 in words is "three hundred ninety-nine million, two hundred twenty-six thousand, eight hundred thirty-one".