40400 has 30 divisors (see below), whose sum is σ = 98022. Its totient is φ = 16000.

The previous prime is 40387. The next prime is 40423. The reversal of 40400 is 404.

Added to its reverse (404) it gives a square (40804 = 202²).

It is a happy number.

40400 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Cunningham number, because it is equal to 201²-1.

It can be written as a sum of positive squares in 3 ways, for example, as 10816 + 29584 = 104^2 + 172^2 .

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 zygodrome in base 7.

It is a congruent number.

It is an unprimeable number.

40400 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 350 + ... + 450.

2⁴⁰⁴⁰⁰ is an apocalyptic number.

40400 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 40400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (49011).

40400 is an abundant number, since it is smaller than the sum of its proper divisors (57622).

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

40400 is a wasteful number, since it uses less digits than its factorization.

40400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119 (or 108 counting only the distinct ones).

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

The square root of 40400 is about 200.9975124224. The cubic root of 40400 is about 34.3131394324.

Adding to 40400 its reverse (404), we get a palindrome (40804).

Multiplying 40400 by its reverse (404), we get a square (16321600 = 4040²).

40400 divided by its reverse (404) gives a square (100 = 10²).

The spelling of 40400 in words is "forty thousand, four hundred", and thus it is an iban number.