400004000 has 96 divisors (see below), whose sum is σ = 1072274112. Its totient is φ = 145440000.

The previous prime is 400003997. The next prime is 400004009. The reversal of 400004000 is 400004.

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 not an unprimeable number, because it can be changed into a prime (400004009) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 39455 + ... + 48545.

It is an arithmetic number, because the mean of its divisors is an integer number (11169522).

Almost surely, 2^400004000 is an apocalyptic number.

400004000 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 400004000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (536137056).

400004000 is an abundant number, since it is smaller than the sum of its proper divisors (672270112).

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

400004000 is a wasteful number, since it uses less digits than its factorization.

400004000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9127 (or 9109 counting only the distinct ones).

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

The square root of 400004000 is about 20000.0999997500. The cubic root of 400004000 is about 736.8087557409.

Adding to 400004000 its reverse (400004), we get a palindrome (400404004).

400004000 divided by its reverse (400004) gives a cube (1000 = 10³).

The spelling of 400004000 in words is "four hundred million, four thousand".