399961040 has 80 divisors (see below), whose sum is σ = 1018662480. Its totient is φ = 145367040.

The previous prime is 399961033. The next prime is 399961063. The reversal of 399961040 is 40169993.

399961040 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 8 ways, for example, as 2835856 + 397125184 = 1684^2 + 19928^2 .

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34370 + ... + 44510.

It is an arithmetic number, because the mean of its divisors is an integer number (12733281).

Almost surely, 2^399961040 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 399961040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (509331240).

399961040 is an abundant number, since it is smaller than the sum of its proper divisors (618701440).

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

399961040 is a wasteful number, since it uses less digits than its factorization.

399961040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10200 (or 10194 counting only the distinct ones).

The product of its (nonzero) digits is 52488, while the sum is 41.

The square root of 399961040 is about 19999.0259762819. The cubic root of 399961040 is about 736.7823773068.

The spelling of 399961040 in words is "three hundred ninety-nine million, nine hundred sixty-one thousand, forty".