400331820 has 48 divisors (see below), whose sum is σ = 1281063168. Its totient is φ = 91504320.

The previous prime is 400331809. The next prime is 400331903. The reversal of 400331820 is 28133004.

It is a happy number.

It is a super-2 number, since 2×400331820² = 320531132209024800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 476166 + ... + 477005.

It is an arithmetic number, because the mean of its divisors is an integer number (26688816).

Almost surely, 2^400331820 is an apocalyptic number.

It is an amenable number.

400331820 is an abundant number, since it is smaller than the sum of its proper divisors (880731348).

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

400331820 is a wasteful number, since it uses less digits than its factorization.

400331820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 953190 (or 953188 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 400331820 is about 20008.2937803302. The cubic root of 400331820 is about 737.0099826387.

Adding to 400331820 its reverse (28133004), we get a palindrome (428464824).

The spelling of 400331820 in words is "four hundred million, three hundred thirty-one thousand, eight hundred twenty".