21225700 has 72 divisors (see below), whose sum is σ = 48996864. Its totient is φ = 7968000.

The previous prime is 21225691. The next prime is 21225713. The reversal of 21225700 is 752212.

It is a congruent number.

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 23 ways as a sum of consecutive naturals, for example, 127017 + ... + 127183.

It is an arithmetic number, because the mean of its divisors is an integer number (680512).

Almost surely, 2^21225700 is an apocalyptic number.

21225700 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 21225700, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24498432).

21225700 is an abundant number, since it is smaller than the sum of its proper divisors (27771164).

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

21225700 is a wasteful number, since it uses less digits than its factorization.

21225700 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 253 (or 246 counting only the distinct ones).

The product of its (nonzero) digits is 280, while the sum is 19.

The square root of 21225700 is about 4607.1357696512. The cubic root of 21225700 is about 276.8772931986.

Adding to 21225700 its reverse (752212), we get a palindrome (21977912).

The spelling of 21225700 in words is "twenty-one million, two hundred twenty-five thousand, seven hundred".