399731089 has 4 divisors (see below), whose sum is σ = 399815280. Its totient is φ = 399646900.

The previous prime is 399731069. The next prime is 399731093. The reversal of 399731089 is 980137993.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 399731089 - 2¹⁷ = 399600017 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399731009) 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, 34519 + ... + 44620.

It is an arithmetic number, because the mean of its divisors is an integer number (99953820).

Almost surely, 2^399731089 is an apocalyptic number.

It is an amenable number.

399731089 is a deficient number, since it is larger than the sum of its proper divisors (84191).

399731089 is an equidigital number, since it uses as much as digits as its factorization.

399731089 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 84190.

The product of its (nonzero) digits is 367416, while the sum is 49.

The square root of 399731089 is about 19993.2760947274. The cubic root of 399731089 is about 736.6411499480.

The spelling of 399731089 in words is "three hundred ninety-nine million, seven hundred thirty-one thousand, eighty-nine".