21652225 has 12 divisors (see below), whose sum is σ = 30684544. Its totient is φ = 14847120.

The previous prime is 21652219. The next prime is 21652273. The reversal of 21652225 is 52225612.

It is a happy number.

It is not a de Polignac number, because 21652225 - 2³ = 21652217 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21652225.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 61689 + ... + 62038.

Almost surely, 2^21652225 is an apocalyptic number.

21652225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21652225 is a deficient number, since it is larger than the sum of its proper divisors (9032319).

21652225 is a wasteful number, since it uses less digits than its factorization.

21652225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123744 (or 123739 counting only the distinct ones).

The product of its digits is 2400, while the sum is 25.

The square root of 21652225 is about 4653.1951388267. The cubic root of 21652225 is about 278.7196002696.

Adding to 21652225 its reverse (52225612), we get a palindrome (73877837).

It can be divided in two parts, 216 and 52225, that added together give a square (52441 = 229²).

The spelling of 21652225 in words is "twenty-one million, six hundred fifty-two thousand, two hundred twenty-five".