399052440 has 128 divisors (see below), whose sum is σ = 1400256000. Its totient is φ = 100808064.

The previous prime is 399052439. The next prime is 399052477. The reversal of 399052440 is 44250993.

399052440 is a `hidden beast` number, since 3 + 9 + 90 + 524 + 40 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 399052395 and 399052404.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 10797 + ... + 30243.

It is an arithmetic number, because the mean of its divisors is an integer number (10939500).

Almost surely, 2^399052440 is an apocalyptic number.

399052440 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 399052440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (700128000).

399052440 is an abundant number, since it is smaller than the sum of its proper divisors (1001203560).

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

399052440 is a wasteful number, since it uses less digits than its factorization.

399052440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19486 (or 19476 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The square root of 399052440 is about 19976.2969541404. The cubic root of 399052440 is about 736.2240328940.

The spelling of 399052440 in words is "three hundred ninety-nine million, fifty-two thousand, four hundred forty".