399112821 has 12 divisors (see below), whose sum is σ = 592077772. Its totient is φ = 258883776.

The previous prime is 399112793. The next prime is 399112823. The reversal of 399112821 is 128211993.

It can be written as a sum of positive squares in 2 ways, for example, as 225900900 + 173211921 = 15030^2 + 13161^2 .

It is not a de Polignac number, because 399112821 - 2⁵ = 399112789 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399112823) 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 11 ways as a sum of consecutive naturals, for example, 598936 + ... + 599601.

Almost surely, 2^399112821 is an apocalyptic number.

It is an amenable number.

399112821 is a deficient number, since it is larger than the sum of its proper divisors (192964951).

399112821 is a wasteful number, since it uses less digits than its factorization.

399112821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1198580 (or 1198577 counting only the distinct ones).

The product of its digits is 7776, while the sum is 36.

The square root of 399112821 is about 19977.8082131149. The cubic root of 399112821 is about 736.2611639382.

The spelling of 399112821 in words is "three hundred ninety-nine million, one hundred twelve thousand, eight hundred twenty-one".