21130225 has 6 divisors (see below), whose sum is σ = 26201510. Its totient is φ = 16904160.

The previous prime is 21130111. The next prime is 21130231. The reversal of 21130225 is 52203112.

It can be written as a sum of positive squares in 3 ways, for example, as 345744 + 20784481 = 588^2 + 4559^2 .

It is not a de Polignac number, because 21130225 - 2¹³ = 21122033 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21130199 and 21130208.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 422580 + ... + 422629.

Almost surely, 2^21130225 is an apocalyptic number.

21130225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21130225 is a deficient number, since it is larger than the sum of its proper divisors (5071285).

21130225 is an equidigital number, since it uses as much as digits as its factorization.

21130225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 845219 (or 845214 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 21130225 is about 4596.7624476364. The cubic root of 21130225 is about 276.4615300071.

Adding to 21130225 its reverse (52203112), we get a palindrome (73333337).

The spelling of 21130225 in words is "twenty-one million, one hundred thirty thousand, two hundred twenty-five".