21456225 has 96 divisors (see below), whose sum is σ = 47616000. Its totient is φ = 9253440.

The previous prime is 21456221. The next prime is 21456251. The reversal of 21456225 is 52265412.

It is not a de Polignac number, because 21456225 - 2² = 21456221 is a prime.

It is a super-3 number, since 3×21456225³ (a number of 23 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21456221) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 89656 + ... + 89894.

It is an arithmetic number, because the mean of its divisors is an integer number (496000).

Almost surely, 2^21456225 is an apocalyptic number.

21456225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21456225 is an abundant number, since it is smaller than the sum of its proper divisors (26159775).

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

21456225 is a wasteful number, since it uses less digits than its factorization.

21456225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 284 (or 273 counting only the distinct ones).

The product of its digits is 4800, while the sum is 27.

The square root of 21456225 is about 4632.0864629236. The cubic root of 21456225 is about 277.8760424197.

The spelling of 21456225 in words is "twenty-one million, four hundred fifty-six thousand, two hundred twenty-five".