399840064 has 56 divisors (see below), whose sum is σ = 860189288. Its totient is φ = 183306240.

The previous prime is 399840059. The next prime is 399840083. The reversal of 399840064 is 460048993.

It can be written as a sum of positive squares in 4 ways, for example, as 53582400 + 346257664 = 7320^2 + 18608^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 399840064.

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 7 ways as a sum of consecutive naturals, for example, 129094 + ... + 132154.

It is an arithmetic number, because the mean of its divisors is an integer number (15360523).

Almost surely, 2^399840064 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 399840064, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (430094644).

399840064 is an abundant number, since it is smaller than the sum of its proper divisors (460349224).

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

399840064 is a wasteful number, since it uses less digits than its factorization.

399840064 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3243 (or 3233 counting only the distinct ones).

The product of its (nonzero) digits is 186624, while the sum is 43.

The square root of 399840064 is about 19996.0012002400. The cubic root of 399840064 is about 736.7080850932.

The spelling of 399840064 in words is "three hundred ninety-nine million, eight hundred forty thousand, sixty-four".