21222600 has 192 divisors, whose sum is σ = 78090240. Its totient is φ = 4665600.

The previous prime is 21222587. The next prime is 21222611. The reversal of 21222600 is 622212.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 21222600.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 130119 + ... + 130281.

It is an arithmetic number, because the mean of its divisors is an integer number (406720).

Almost surely, 2^21222600 is an apocalyptic number.

21222600 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 21222600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39045120).

21222600 is an abundant number, since it is smaller than the sum of its proper divisors (56867640).

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

21222600 is a wasteful number, since it uses less digits than its factorization.

21222600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 220 (or 211 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 21222600 is about 4606.7993227402. The cubic root of 21222600 is about 276.8638132914.

Adding to 21222600 its reverse (622212), we get a palindrome (21844812).

The spelling of 21222600 in words is "twenty-one million, two hundred twenty-two thousand, six hundred".