399720880 has 80 divisors (see below), whose sum is σ = 1006435584. Its totient is φ = 146764800.

The previous prime is 399720877. The next prime is 399720883. The reversal of 399720880 is 88027993.

It is an interprime number because it is at equal distance from previous prime (399720877) and next prime (399720883).

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

It is a self number, because there is not a number n which added to its sum of digits gives 399720880.

It is not an unprimeable number, because it can be changed into a prime (399720883) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 203905 + ... + 205855.

Almost surely, 2^399720880 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 399720880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (503217792).

399720880 is an abundant number, since it is smaller than the sum of its proper divisors (606714704).

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

399720880 is a wasteful number, since it uses less digits than its factorization.

399720880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2174 (or 2168 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 46.

The square root of 399720880 is about 19993.0207822630. The cubic root of 399720880 is about 736.6348787040.

The spelling of 399720880 in words is "three hundred ninety-nine million, seven hundred twenty thousand, eight hundred eighty".