399401688 has 128 divisors (see below), whose sum is σ = 1197734400. Its totient is φ = 108573696.

The previous prime is 399401687. The next prime is 399401699. The reversal of 399401688 is 886104993.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399401687) 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, 355095 + ... + 356217.

It is an arithmetic number, because the mean of its divisors is an integer number (9357300).

Almost surely, 2^399401688 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 399401688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (598867200).

399401688 is an abundant number, since it is smaller than the sum of its proper divisors (798332712).

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

399401688 is a wasteful number, since it uses less digits than its factorization.

399401688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1241 (or 1237 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 48.

The square root of 399401688 is about 19985.0366024183. The cubic root of 399401688 is about 736.4387497001.

The spelling of 399401688 in words is "three hundred ninety-nine million, four hundred one thousand, six hundred eighty-eight".