21312200 has 96 divisors (see below), whose sum is σ = 61037760. Its totient is φ = 6739200.

The previous prime is 21312173. The next prime is 21312223. The reversal of 21312200 is 221312.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 17615 + ... + 18785.

It is an arithmetic number, because the mean of its divisors is an integer number (635810).

Almost surely, 2^21312200 is an apocalyptic number.

21312200 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 21312200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30518880).

21312200 is an abundant number, since it is smaller than the sum of its proper divisors (39725560).

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

21312200 is a wasteful number, since it uses less digits than its factorization.

21312200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1207 (or 1198 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 11.

The square root of 21312200 is about 4616.5138362188. The cubic root of 21312200 is about 277.2528980143.

Adding to 21312200 its reverse (221312), we get a palindrome (21533512).

It can be divided in two parts, 21312 and 200, that added together give a palindrome (21512).

The spelling of 21312200 in words is "twenty-one million, three hundred twelve thousand, two hundred".