21112400 has 60 divisors (see below), whose sum is σ = 51847872. Its totient is φ = 8257920.

The previous prime is 21112381. The next prime is 21112411. The reversal of 21112400 is 421112.

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, 18239 + ... + 19361.

Almost surely, 2^21112400 is an apocalyptic number.

21112400 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 21112400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25923936).

21112400 is an abundant number, since it is smaller than the sum of its proper divisors (30735472).

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

21112400 is a wasteful number, since it uses less digits than its factorization.

21112400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1188 (or 1177 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 21112400 is about 4594.8231739644. The cubic root of 21112400 is about 276.3837691515.

Adding to 21112400 its reverse (421112), we get a palindrome (21533512).

It can be divided in two parts, 21112 and 400, that added together give a palindrome (21512).

The spelling of 21112400 in words is "twenty-one million, one hundred twelve thousand, four hundred".