400400000000 has 792 divisors, whose sum is σ = 1343343062208. Its totient is φ = 115200000000.

The previous prime is 400399999997. The next prime is 400400000029. The reversal of 400400000000 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 an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 30799999994 + ... + 30800000006.

Almost surely, 2^400400000000 is an apocalyptic number.

400400000000 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 400400000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (671671531104).

400400000000 is an abundant number, since it is smaller than the sum of its proper divisors (942943062208).

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

400400000000 is an frugal number, since it uses more digits than its factorization.

400400000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91 (or 38 counting only the distinct ones).

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

Adding to 400400000000 its reverse (4004), we get a palindrome (400400004004).

400400000000 divided by its reverse (4004) gives a 8-th power (100000000 = 10⁸).

It can be divided in two parts, 400 and 400000000, that multiplied together give a square (160000000000 = 400000²).

The spelling of 400400000000 in words is "four hundred billion, four hundred million", and thus it is an aban number.