399557989 has 4 divisors (see below), whose sum is σ = 399999424. Its totient is φ = 399116556.

The previous prime is 399557957. The next prime is 399557993. The reversal of 399557989 is 989755993.

It is a happy number.

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 399557989 - 2⁵ = 399557957 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 399557989.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399557189) 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, 219357 + ... + 221170.

It is an arithmetic number, because the mean of its divisors is an integer number (99999856).

Almost surely, 2^399557989 is an apocalyptic number.

It is an amenable number.

399557989 is a deficient number, since it is larger than the sum of its proper divisors (441435).

399557989 is an equidigital number, since it uses as much as digits as its factorization.

399557989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 441434.

The product of its digits is 27556200, while the sum is 64.

The square root of 399557989 is about 19988.9466705977. The cubic root of 399557989 is about 736.5348026251.

The spelling of 399557989 in words is "three hundred ninety-nine million, five hundred fifty-seven thousand, nine hundred eighty-nine".