399608640 has 224 divisors, whose sum is σ = 1429633920. Its totient is φ = 106375680.

The previous prime is 399608633. The next prime is 399608663. The reversal of 399608640 is 46806993.

399608640 is a `hidden beast` number, since 39 + 9 + 608 + 6 + 4 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 699555 + ... + 700125.

Almost surely, 2^399608640 is an apocalyptic number.

399608640 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 399608640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (714816960).

399608640 is an abundant number, since it is smaller than the sum of its proper divisors (1030025280).

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

399608640 is an frugal number, since it uses more digits than its factorization.

399608640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 609 (or 581 counting only the distinct ones).

The product of its (nonzero) digits is 279936, while the sum is 45.

The square root of 399608640 is about 19990.2136056621. The cubic root of 399608640 is about 736.5659242220.

The spelling of 399608640 in words is "three hundred ninety-nine million, six hundred eight thousand, six hundred forty".