21828625 has 64 divisors (see below), whose sum is σ = 35642880. Its totient is φ = 12960000.

The previous prime is 21828623. The next prime is 21828659. The reversal of 21828625 is 52682812.

It is not a de Polignac number, because 21828625 - 2¹ = 21828623 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21828623) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 216075 + ... + 216175.

It is an arithmetic number, because the mean of its divisors is an integer number (556920).

Almost surely, 2^21828625 is an apocalyptic number.

21828625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21828625 is a deficient number, since it is larger than the sum of its proper divisors (13814255).

21828625 is a wasteful number, since it uses less digits than its factorization.

21828625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 155 (or 145 counting only the distinct ones).

The product of its digits is 15360, while the sum is 34.

The square root of 21828625 is about 4672.1114070621. Note that the first 3 decimals coincide. The cubic root of 21828625 is about 279.4744606471.

The spelling of 21828625 in words is "twenty-one million, eight hundred twenty-eight thousand, six hundred twenty-five".