Adding to 400400 its reverse (4004), we get a palindrome (404404).
Multipling 400400 by its reverse (4004), we get a square (1603201600 = 400402).
400400 divided by its reverse (4004) gives a square (100 = 102).
It is a happy number.
It is a super Niven number, because it is divisible the sum of any subset of its (nonzero) digits.
400400 is an untouchable number, because it is not equal to the sum of proper divisors of any number.
2400400 is an apocalyptic number.
400400 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 400400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (645792).
It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.
400400 is a wasteful number, since it uses less digits than its factorization.
400400 is an evil number, because the sum of its binary digits is even.
The square root of 400400 is about 632.7716807823. The cubic root of 400400 is about 73.7051820006.
The spelling of 400400 in words is "four hundred thousand, four hundred", and thus it is an iban number.