399640000000 has 320 divisors, whose sum is σ = 1018202080896. Its totient is φ = 156672000000.

The previous prime is 399639999977. The next prime is 399640000063. The reversal of 399640000000 is 46993.

It is a tau number, because it is divible by the number of its divisors (320).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 3879999949 + ... + 3880000051.

Almost surely, 2^399640000000 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 399640000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (509101040448).

399640000000 is an abundant number, since it is smaller than the sum of its proper divisors (618562080896).

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

399640000000 is an frugal number, since it uses more digits than its factorization.

399640000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253 (or 207 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 31.

Adding to 399640000000 its reverse (46993), we get a palindrome (399640046993).

The spelling of 399640000000 in words is "three hundred ninety-nine billion, six hundred forty million", and thus it is an aban number.