399991696 has 20 divisors (see below), whose sum is σ = 834598492. Its totient is φ = 184611456.

The previous prime is 399991663. The next prime is 399991727. The reversal of 399991696 is 696199993.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 242238096 + 157753600 = 15564^2 + 12560^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 961311 + ... + 961726.

Almost surely, 2^399991696 is an apocalyptic number.

It is an amenable number.

399991696 is an abundant number, since it is smaller than the sum of its proper divisors (434606796).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

399991696 is a wasteful number, since it uses less digits than its factorization.

399991696 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1923058 (or 1923052 counting only the distinct ones).

The product of its digits is 6377292, while the sum is 61.

The square root of 399991696 is about 19999.7923989225. The cubic root of 399991696 is about 736.8012009932.

The spelling of 399991696 in words is "three hundred ninety-nine million, nine hundred ninety-one thousand, six hundred ninety-six".