399159881 has 4 divisors (see below), whose sum is σ = 422639892. Its totient is φ = 375679872.

The previous prime is 399159863. The next prime is 399159889. The reversal of 399159881 is 188951993.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 188951993 = 67 ⋅2820179.

It can be written as a sum of positive squares in 2 ways, for example, as 359671225 + 39488656 = 18965^2 + 6284^2 .

It is not a de Polignac number, because 399159881 - 2²² = 394965577 is a prime.

It is a super-2 number, since 2×399159881² = 318657221199868322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399159889) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11739980 + ... + 11740013.

It is an arithmetic number, because the mean of its divisors is an integer number (105659973).

Almost surely, 2^399159881 is an apocalyptic number.

It is an amenable number.

399159881 is a deficient number, since it is larger than the sum of its proper divisors (23480011).

399159881 is a wasteful number, since it uses less digits than its factorization.

399159881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23480010.

The product of its digits is 699840, while the sum is 53.

The square root of 399159881 is about 19978.9859852796. The cubic root of 399159881 is about 736.2901006923.

The spelling of 399159881 in words is "three hundred ninety-nine million, one hundred fifty-nine thousand, eight hundred eighty-one".