399881636 has 24 divisors (see below), whose sum is σ = 872469696. Its totient is φ = 155797920.

The previous prime is 399881621. The next prime is 399881653. The reversal of 399881636 is 636188993.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 648851 + ... + 649466.

It is an arithmetic number, because the mean of its divisors is an integer number (36352904).

Almost surely, 2^399881636 is an apocalyptic number.

It is an amenable number.

399881636 is an abundant number, since it is smaller than the sum of its proper divisors (472588060).

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

399881636 is a wasteful number, since it uses less digits than its factorization.

399881636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1298339 (or 1298337 counting only the distinct ones).

The product of its digits is 1679616, while the sum is 53.

The square root of 399881636 is about 19997.0406810608. The cubic root of 399881636 is about 736.7336164410.

The spelling of 399881636 in words is "three hundred ninety-nine million, eight hundred eighty-one thousand, six hundred thirty-six".