399543900 has 144 divisors (see below), whose sum is σ = 1343247360. Its totient is φ = 89798400.

The previous prime is 399543899. The next prime is 399543919. The reversal of 399543900 is 9345993.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 126541 + ... + 129659.

Almost surely, 2^399543900 is an apocalyptic number.

399543900 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 399543900, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (671623680).

399543900 is an abundant number, since it is smaller than the sum of its proper divisors (943703460).

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

399543900 is a wasteful number, since it uses less digits than its factorization.

399543900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3204 (or 3197 counting only the distinct ones).

The product of its (nonzero) digits is 131220, while the sum is 42.

The square root of 399543900 is about 19988.5942477204. The cubic root of 399543900 is about 736.5261454247.

It can be divided in two parts, 3995 and 43900, that added together give a triangular number (47895 = T₃₀₉).

The spelling of 399543900 in words is "three hundred ninety-nine million, five hundred forty-three thousand, nine hundred".