21228825 has 12 divisors (see below), whose sum is σ = 35098448. Its totient is φ = 11322000.

The previous prime is 21228811. The next prime is 21228829. The reversal of 21228825 is 52882212.

It is not a de Polignac number, because 21228825 - 2⁶ = 21228761 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21228792 and 21228801.

It is not an unprimeable number, because it can be changed into a prime (21228829) by changing a digit.

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 11 ways as a sum of consecutive naturals, for example, 141451 + ... + 141600.

Almost surely, 2^21228825 is an apocalyptic number.

21228825 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21228825 is a deficient number, since it is larger than the sum of its proper divisors (13869623).

21228825 is a wasteful number, since it uses less digits than its factorization.

21228825 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 283064 (or 283059 counting only the distinct ones).

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

The square root of 21228825 is about 4607.4749049778. The cubic root of 21228825 is about 276.8908804864.

The spelling of 21228825 in words is "twenty-one million, two hundred twenty-eight thousand, eight hundred twenty-five".