399638528 has 36 divisors (see below), whose sum is σ = 799536150. Its totient is φ = 199753728.

The previous prime is 399638513. The next prime is 399638537. The reversal of 399638528 is 825836993.

It can be written as a sum of positive squares in only one way, i.e., 388562944 + 11075584 = 19712^2 + 3328^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 399638528.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 129548 + ... + 132596.

Almost surely, 2^399638528 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 399638528, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (399768075).

399638528 is an abundant number, since it is smaller than the sum of its proper divisors (399897622).

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

399638528 is an frugal number, since it uses more digits than its factorization.

399638528 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3083 (or 3051 counting only the distinct ones).

The product of its digits is 2799360, while the sum is 53.

The square root of 399638528 is about 19990.9611574831. The cubic root of 399638528 is about 736.5842871329.

It can be divided in two parts, 3996 and 38528, that added together give a palindrome (42524).

The spelling of 399638528 in words is "three hundred ninety-nine million, six hundred thirty-eight thousand, five hundred twenty-eight".