22400 has 48 divisors (see below), whose sum is σ = 63240. Its totient is φ = 7680.

The previous prime is 22397. The next prime is 22409. The reversal of 22400 is 422.

It is a Harshad number since it is a multiple of its sum of digits (8).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (22409) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3197 + ... + 3203.

2²²⁴⁰⁰ is an apocalyptic number.

22400 is a gapful number since it is divisible by the number (20) 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 22400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31620).

22400 is an abundant number, since it is smaller than the sum of its proper divisors (40840).

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

22400 is an equidigital number, since it uses as much as digits as its factorization.

22400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 31 (or 14 counting only the distinct ones).

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

The square root of 22400 is about 149.6662954710. Note that the first 3 decimals coincide. The cubic root of 22400 is about 28.1891949283.

Adding to 22400 its reverse (422), we get a palindrome (22822).

The spelling of 22400 in words is "twenty-two thousand, four hundred", and thus it is an iban number.