21324625 has 16 divisors (see below), whose sum is σ = 30416256. Its totient is φ = 14622000.

The previous prime is 21324619. The next prime is 21324629. The reversal of 21324625 is 52642312.

It is not a de Polignac number, because 21324625 - 2⁹ = 21324113 is a prime.

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 21324625.

It is not an unprimeable number, because it can be changed into a prime (21324629) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11311 + ... + 13060.

It is an arithmetic number, because the mean of its divisors is an integer number (1901016).

Almost surely, 2^21324625 is an apocalyptic number.

21324625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21324625 is a deficient number, since it is larger than the sum of its proper divisors (9091631).

21324625 is an equidigital number, since it uses as much as digits as its factorization.

21324625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24393 (or 24383 counting only the distinct ones).

The product of its digits is 2880, while the sum is 25.

The square root of 21324625 is about 4617.8593525572. The cubic root of 21324625 is about 277.3067669724.

Adding to 21324625 its reverse (52642312), we get a palindrome (73966937).

The spelling of 21324625 in words is "twenty-one million, three hundred twenty-four thousand, six hundred twenty-five".