399644784 has 360 divisors, whose sum is σ = 1499546880. Its totient is φ = 97977600.

The previous prime is 399644759. The next prime is 399644801. The reversal of 399644784 is 487446993.

It is a happy number.

399644784 is a `hidden beast` number, since 39 + 96 + 447 + 84 = 666.

It is a nude number because it is divisible by every one of its digits.

It is a self number, because there is not a number n which added to its sum of digits gives 399644784.

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 71 ways as a sum of consecutive naturals, for example, 1474569 + ... + 1474839.

It is an arithmetic number, because the mean of its divisors is an integer number (4165408).

Almost surely, 2^399644784 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 399644784, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (749773440).

399644784 is an abundant number, since it is smaller than the sum of its proper divisors (1099902096).

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

399644784 is a wasteful number, since it uses less digits than its factorization.

399644784 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 329 (or 313 counting only the distinct ones).

The product of its digits is 5225472, while the sum is 54.

The square root of 399644784 is about 19991.1176275865. The cubic root of 399644784 is about 736.5881306456.

The spelling of 399644784 in words is "three hundred ninety-nine million, six hundred forty-four thousand, seven hundred eighty-four".