21229225 has 12 divisors (see below), whose sum is σ = 26418076. Its totient is φ = 16922880.

The previous prime is 21229199. The next prime is 21229237. The reversal of 21229225 is 52292212.

It can be written as a sum of positive squares in 6 ways, for example, as 535824 + 20693401 = 732^2 + 4549^2 .

It is not a de Polignac number, because 21229225 - 2¹¹ = 21227177 is a prime.

It is a hoax number, since the sum of its digits (25) coincides with the sum of the digits of its distinct prime factors.

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 21229225.

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, 6469 + ... + 9181.

Almost surely, 2^21229225 is an apocalyptic number.

21229225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21229225 is a deficient number, since it is larger than the sum of its proper divisors (5188851).

21229225 is a wasteful number, since it uses less digits than its factorization.

21229225 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3036 (or 3031 counting only the distinct ones).

The product of its digits is 1440, while the sum is 25.

The square root of 21229225 is about 4607.5183124975. The cubic root of 21229225 is about 276.8926195630.

The spelling of 21229225 in words is "twenty-one million, two hundred twenty-nine thousand, two hundred twenty-five".