399392091 has 18 divisors (see below), whose sum is σ = 671088132. Its totient is φ = 228223800.

The previous prime is 399392083. The next prime is 399392093. The reversal of 399392091 is 190293993.

It is not a de Polignac number, because 399392091 - 2³ = 399392083 is a prime.

It is not an unprimeable number, because it can be changed into a prime (399392093) 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 in 17 ways as a sum of consecutive naturals, for example, 452385 + ... + 453266.

It is an arithmetic number, because the mean of its divisors is an integer number (37282674).

Almost surely, 2^399392091 is an apocalyptic number.

399392091 is a deficient number, since it is larger than the sum of its proper divisors (271696041).

399392091 is a wasteful number, since it uses less digits than its factorization.

399392091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 905671 (or 905661 counting only the distinct ones).

The product of its (nonzero) digits is 118098, while the sum is 45.

The square root of 399392091 is about 19984.7964963369. The cubic root of 399392091 is about 736.4328511611.

The spelling of 399392091 in words is "three hundred ninety-nine million, three hundred ninety-two thousand, ninety-one".