399874091 has 2 divisors, whose sum is σ = 399874092. Its totient is φ = 399874090.

The previous prime is 399874081. The next prime is 399874147. The reversal of 399874091 is 190478993.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-399874091 is a prime.

It is not a weakly prime, because it can be changed into another prime (399874031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 199937045 + 199937046.

It is an arithmetic number, because the mean of its divisors is an integer number (199937046).

Almost surely, 2^399874091 is an apocalyptic number.

399874091 is a deficient number, since it is larger than the sum of its proper divisors (1).

399874091 is an equidigital number, since it uses as much as digits as its factorization.

399874091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 489888, while the sum is 50.

The square root of 399874091 is about 19996.8520272567. The cubic root of 399874091 is about 736.7289828281.

The spelling of 399874091 in words is "three hundred ninety-nine million, eight hundred seventy-four thousand, ninety-one".