21331200 has 216 divisors, whose sum is σ = 77557536. Its totient is φ = 5120000.

The previous prime is 21331187. The next prime is 21331201. The reversal of 21331200 is 213312.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21331201) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 211150 + ... + 211250.

Almost surely, 2^21331200 is an apocalyptic number.

21331200 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 21331200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38778768).

21331200 is an abundant number, since it is smaller than the sum of its proper divisors (56226336).

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

21331200 is a wasteful number, since it uses less digits than its factorization.

21331200 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141 (or 122 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 12.

The square root of 21331200 is about 4618.5712076355. The cubic root of 21331200 is about 277.3352646151.

Adding to 21331200 its reverse (213312), we get a palindrome (21544512).

Multiplying 21331200 by its reverse (213312), we get a square (4550200934400 = 2133120²).

21331200 divided by its reverse (213312) gives a square (100 = 10²).

It can be divided in two parts, 2133 and 1200, that added together give a palindrome (3333).

The spelling of 21331200 in words is "twenty-one million, three hundred thirty-one thousand, two hundred".