399520 has 48 divisors (see below), whose sum is σ = 1034208. Its totient is φ = 144640.

The previous prime is 399499. The next prime is 399523. The reversal of 399520 is 25993.

399520 = T₂₆₄ + T₂₆₅ + ... + T₂₇₄.

It is a Smith number, since the sum of its digits (28) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (399523) by changing a digit.

399520 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1647 + ... + 1873.

It is an arithmetic number, because the mean of its divisors is an integer number (21546).

2³⁹⁹⁵²⁰ 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 399520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (517104).

399520 is an abundant number, since it is smaller than the sum of its proper divisors (634688).

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

399520 is a wasteful number, since it uses less digits than its factorization.

399520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253 (or 245 counting only the distinct ones).

The product of its (nonzero) digits is 2430, while the sum is 28.

The square root of 399520 is about 632.0759448041. The cubic root of 399520 is about 73.6511459241.

It can be divided in two parts, 399 and 520, that added together give a palindrome (919).

The spelling of 399520 in words is "three hundred ninety-nine thousand, five hundred twenty".