400400000 has 384 divisors, whose sum is σ = 1338664320. Its totient is φ = 115200000.

The previous prime is 400399949. The next prime is 400400041. The reversal of 400400000 is 4004.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (8).

It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.

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, 30799994 + ... + 30800006.

It is an arithmetic number, because the mean of its divisors is an integer number (3486105).

Almost surely, 2^400400000 is an apocalyptic number.

400400000 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 400400000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (669332160).

400400000 is an abundant number, since it is smaller than the sum of its proper divisors (938264320).

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

400400000 is an equidigital number, since it uses as much as digits as its factorization.

400400000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70 (or 38 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 8.

The square root of 400400000 is about 20009.9975012492. The cubic root of 400400000 is about 737.0518200061.

Adding to 400400000 its reverse (4004), we get a palindrome (400404004).

400400000 divided by its reverse (4004) gives a 5-th power (100000 = 10⁵).

The spelling of 400400000 in words is "four hundred million, four hundred thousand".