399191328 has 120 divisors (see below), whose sum is σ = 1180070892. Its totient is φ = 132378624.

The previous prime is 399191327. The next prime is 399191329. The reversal of 399191328 is 823191993.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (399191327) and next prime (399191329).

It can be written as a sum of positive squares in 2 ways, for example, as 396328464 + 2862864 = 19908^2 + 1692^2 .

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (399191321) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 873276 + ... + 873732.

Almost surely, 2^399191328 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 399191328, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (590035446).

399191328 is an abundant number, since it is smaller than the sum of its proper divisors (780879564).

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

399191328 is a wasteful number, since it uses less digits than its factorization.

399191328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 816 (or 799 counting only the distinct ones).

The product of its digits is 104976, while the sum is 45.

The square root of 399191328 is about 19979.7729716831. The cubic root of 399191328 is about 736.3094358909.

The spelling of 399191328 in words is "three hundred ninety-nine million, one hundred ninety-one thousand, three hundred twenty-eight".