21624125 has 8 divisors (see below), whose sum is σ = 26987064. Its totient is φ = 17299200.

The previous prime is 21624107. The next prime is 21624137. The reversal of 21624125 is 52142612.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 38809 + 21585316 = 197^2 + 4646^2 .

It is not a de Polignac number, because 21624125 - 2⁶ = 21624061 is a prime.

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 21624125.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 86372 + ... + 86621.

It is an arithmetic number, because the mean of its divisors is an integer number (3373383).

Almost surely, 2^21624125 is an apocalyptic number.

21624125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21624125 is a deficient number, since it is larger than the sum of its proper divisors (5362939).

21624125 is an equidigital number, since it uses as much as digits as its factorization.

21624125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 173008 (or 172998 counting only the distinct ones).

The product of its digits is 960, while the sum is 23.

The square root of 21624125 is about 4650.1747279000. The cubic root of 21624125 is about 278.5989750788.

Adding to 21624125 its reverse (52142612), we get a palindrome (73766737).

The spelling of 21624125 in words is "twenty-one million, six hundred twenty-four thousand, one hundred twenty-five".