400000400 has 60 divisors (see below), whose sum is σ = 970613844. Its totient is φ = 158400000.

The previous prime is 400000373. The next prime is 400000411. The reversal of 400000400 is 4000004.

It is a happy number.

It can be written as a sum of positive squares in 6 ways, for example, as 73547776 + 326452624 = 8576^2 + 18068^2 .

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 11 ways as a sum of consecutive naturals, for example, 35450 + ... + 45350.

Almost surely, 2^400000400 is an apocalyptic number.

400000400 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 400000400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (485306922).

400000400 is an abundant number, since it is smaller than the sum of its proper divisors (570613444).

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

400000400 is a wasteful number, since it uses less digits than its factorization.

400000400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10020 (or 10009 counting only the distinct ones).

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

The square root of 400000400 is about 20000.0099999975. The cubic root of 400000400 is about 736.8065453301.

Adding to 400000400 its reverse (4000004), we get a palindrome (404000404).

400000400 divided by its reverse (4000004) gives a square (100 = 10²).

The spelling of 400000400 in words is "four hundred million, four hundred", and thus it is an aban number.