399243139 has 2 divisors, whose sum is σ = 399243140. Its totient is φ = 399243138.

The previous prime is 399243133. The next prime is 399243193. The reversal of 399243139 is 931342993.

It is a happy number.

Together with next prime (399243193) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 399243139 - 2¹⁹ = 398718851 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 399243095 and 399243104.

It is not a weakly prime, because it can be changed into another prime (399243133) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199621569 + 199621570.

It is an arithmetic number, because the mean of its divisors is an integer number (199621570).

Almost surely, 2^399243139 is an apocalyptic number.

399243139 is a deficient number, since it is larger than the sum of its proper divisors (1).

399243139 is an equidigital number, since it uses as much as digits as its factorization.

399243139 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 157464, while the sum is 43.

The square root of 399243139 is about 19981.0695159193. The cubic root of 399243139 is about 736.3412896873.

The spelling of 399243139 in words is "three hundred ninety-nine million, two hundred forty-three thousand, one hundred thirty-nine".