399589840 has 80 divisors (see below), whose sum is σ = 1035090000. Its totient is φ = 142442496.

The previous prime is 399589837. The next prime is 399589847. The reversal of 399589840 is 48985993.

It can be written as a sum of positive squares in 8 ways, for example, as 54819216 + 344770624 = 7404^2 + 18568^2 .

It is a tau number, because it is divible by the number of its divisors (80).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (399589847) 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 15 ways as a sum of consecutive naturals, for example, 23536 + ... + 36784.

It is an arithmetic number, because the mean of its divisors is an integer number (12938625).

It is the magic constant of a 928 × 928 magic square.

Almost surely, 2^399589840 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 399589840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (517545000).

399589840 is an abundant number, since it is smaller than the sum of its proper divisors (635500160).

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

399589840 is a wasteful number, since it uses less digits than its factorization.

399589840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13304 (or 13298 counting only the distinct ones).

The product of its (nonzero) digits is 2799360, while the sum is 55.

The square root of 399589840 is about 19989.7433700385. The cubic root of 399589840 is about 736.5543732067.

The spelling of 399589840 in words is "three hundred ninety-nine million, five hundred eighty-nine thousand, eight hundred forty".