399840016 has 15 divisors (see below), whose sum is σ = 774845031. Its totient is φ = 199880016.

The previous prime is 399840011. The next prime is 399840029. The reversal of 399840016 is 610048993.

The square root of 399840016 is 19996.

It is a perfect power (a square), and thus also a powerful number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (399840011) by changing a digit.

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 2 ways as a sum of consecutive naturals, for example, 77485 + ... + 82483.

Almost surely, 2^399840016 is an apocalyptic number.

399840016 is the 19996-th square number.

It is an amenable number.

399840016 is a deficient number, since it is larger than the sum of its proper divisors (375005015).

399840016 is an frugal number, since it uses more digits than its factorization.

399840016 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10006 (or 5001 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 40.

The cubic root of 399840016 is about 736.7080556131.

Multiplying 399840016 by its product of nonzero digits (46656), we get a square (18654935786496 = 4319136²).

The spelling of 399840016 in words is "three hundred ninety-nine million, eight hundred forty thousand, sixteen".