21828225 has 12 divisors (see below), whose sum is σ = 36089456. Its totient is φ = 11641680.

The previous prime is 21828223. The next prime is 21828227. The reversal of 21828225 is 52282812.

It is an interprime number because it is at equal distance from previous prime (21828223) and next prime (21828227).

It is not a de Polignac number, because 21828225 - 2¹ = 21828223 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21828192 and 21828201.

It is not an unprimeable number, because it can be changed into a prime (21828223) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 145447 + ... + 145596.

Almost surely, 2^21828225 is an apocalyptic number.

21828225 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21828225 is a deficient number, since it is larger than the sum of its proper divisors (14261231).

21828225 is a wasteful number, since it uses less digits than its factorization.

21828225 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 291056 (or 291051 counting only the distinct ones).

The product of its digits is 5120, while the sum is 30.

The square root of 21828225 is about 4672.0685996676. The cubic root of 21828225 is about 279.4727535543.

The spelling of 21828225 in words is "twenty-one million, eight hundred twenty-eight thousand, two hundred twenty-five".