399155191 has 2 divisors, whose sum is σ = 399155192. Its totient is φ = 399155190.

The previous prime is 399155129. The next prime is 399155201. The reversal of 399155191 is 191551993.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 399155191 - 2⁷ = 399155063 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (399152191) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199577595 + 199577596.

It is an arithmetic number, because the mean of its divisors is an integer number (199577596).

Almost surely, 2^399155191 is an apocalyptic number.

399155191 is a deficient number, since it is larger than the sum of its proper divisors (1).

399155191 is an equidigital number, since it uses as much as digits as its factorization.

399155191 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 54675, while the sum is 43.

The square root of 399155191 is about 19978.8686116106. The cubic root of 399155191 is about 736.2872169572.

The spelling of 399155191 in words is "three hundred ninety-nine million, one hundred fifty-five thousand, one hundred ninety-one".