400400800 has 36 divisors (see below), whose sum is σ = 977480406. Its totient is φ = 160160000.

The previous prime is 400400773. The next prime is 400400807. The reversal of 400400800 is 8004004.

It can be written as a sum of positive squares in 3 ways, for example, as 324432144 + 75968656 = 18012^2 + 8716^2 .

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

It is not an unprimeable number, because it can be changed into a prime (400400807) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 249451 + ... + 251050.

Almost surely, 2^400400800 is an apocalyptic number.

400400800 is a gapful number since it is divisible by the number (40) formed by its first and last digit.

It is an amenable number.

400400800 is an abundant number, since it is smaller than the sum of its proper divisors (577079606).

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

400400800 is a wasteful number, since it uses less digits than its factorization.

400400800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 500521 (or 500508 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 400400800 is about 20010.0174912467. The cubic root of 400400800 is about 737.0523108827.

Adding to 400400800 its reverse (8004004), we get a palindrome (408404804).

The spelling of 400400800 in words is "four hundred million, four hundred thousand, eight hundred".