399423728 has 80 divisors (see below), whose sum is σ = 881193600. Its totient is φ = 173725440.

The previous prime is 399423707. The next prime is 399423733. The reversal of 399423728 is 827324993.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 709175 + ... + 709737.

It is an arithmetic number, because the mean of its divisors is an integer number (11014920).

Almost surely, 2^399423728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 399423728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (440596800).

399423728 is an abundant number, since it is smaller than the sum of its proper divisors (481769872).

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

399423728 is a wasteful number, since it uses less digits than its factorization.

399423728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 750 (or 744 counting only the distinct ones).

The product of its digits is 653184, while the sum is 47.

The square root of 399423728 is about 19985.5880073617. The cubic root of 399423728 is about 736.4522956381.

The spelling of 399423728 in words is "three hundred ninety-nine million, four hundred twenty-three thousand, seven hundred twenty-eight".