399397728 has 192 divisors, whose sum is σ = 1170505728. Its totient is φ = 118702080.

The previous prime is 399397697. The next prime is 399397729. The reversal of 399397728 is 827793993.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399397729) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3144801 + ... + 3144927.

It is an arithmetic number, because the mean of its divisors is an integer number (6096384).

Almost surely, 2^399397728 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 399397728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (585252864).

399397728 is an abundant number, since it is smaller than the sum of its proper divisors (771108000).

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

399397728 is a wasteful number, since it uses less digits than its factorization.

399397728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 245 (or 237 counting only the distinct ones).

The product of its digits is 5143824, while the sum is 57.

The square root of 399397728 is about 19984.9375280485. The cubic root of 399397728 is about 736.4363158036.

The spelling of 399397728 in words is "three hundred ninety-nine million, three hundred ninety-seven thousand, seven hundred twenty-eight".