400404400 has 240 divisors, whose sum is σ = 1143328608. Its totient is φ = 133120000.

The previous prime is 400404391. The next prime is 400404449. The reversal of 400404400 is 4404004.

It is a Harshad number since it is a multiple of its sum of digits (16).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 3964350 + ... + 3964450.

Almost surely, 2^400404400 is an apocalyptic number.

400404400 is a gapful number since it is divisible by the number (40) 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 400404400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (571664304).

400404400 is an abundant number, since it is smaller than the sum of its proper divisors (742924208).

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

400404400 is a wasteful number, since it uses less digits than its factorization.

400404400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200 (or 189 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 16.

The square root of 400404400 is about 20010.1074459884. The cubic root of 400404400 is about 737.0545198197.

Adding to 400404400 its reverse (4404004), we get a palindrome (404808404).

The spelling of 400404400 in words is "four hundred million, four hundred four thousand, four hundred".