21225600 has 288 divisors, whose sum is σ = 83856240. Its totient is φ = 5068800.

The previous prime is 21225583. The next prime is 21225613. The reversal of 21225600 is 652212.

It is a tau number, because it is divible by the number of its divisors (288).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 316767 + ... + 316833.

Almost surely, 2^21225600 is an apocalyptic number.

21225600 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 21225600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (41928120).

21225600 is an abundant number, since it is smaller than the sum of its proper divisors (62630640).

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

21225600 is a wasteful number, since it uses less digits than its factorization.

21225600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108 (or 88 counting only the distinct ones).

The product of its (nonzero) digits is 240, while the sum is 18.

The square root of 21225600 is about 4607.1249169086. The cubic root of 21225600 is about 276.8768583834.

Adding to 21225600 its reverse (652212), we get a palindrome (21877812).

The spelling of 21225600 in words is "twenty-one million, two hundred twenty-five thousand, six hundred".