399728 has 40 divisors (see below), whose sum is σ = 916608. Its totient is φ = 165312.

The previous prime is 399727. The next prime is 399731. The reversal of 399728 is 827993.

It is a junction number, because it is equal to n+sod(n) for n = 399691 and 399700.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4775 + ... + 4857.

2³⁹⁹⁷²⁸ 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 399728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (458304).

399728 is an abundant number, since it is smaller than the sum of its proper divisors (516880).

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

399728 is a wasteful number, since it uses less digits than its factorization.

399728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141 (or 135 counting only the distinct ones).

The product of its digits is 27216, while the sum is 38.

The square root of 399728 is about 632.2404605844. The cubic root of 399728 is about 73.6639252430.

The spelling of 399728 in words is "three hundred ninety-nine thousand, seven hundred twenty-eight".