21345625 has 60 divisors (see below), whose sum is σ = 33654852. Its totient is φ = 13440000.

The previous prime is 21345619. The next prime is 21345629. The reversal of 21345625 is 52654312.

It can be written as a sum of positive squares in 10 ways, for example, as 18593344 + 2752281 = 4312^2 + 1659^2 .

It is not a de Polignac number, because 21345625 - 2⁵ = 21345593 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21345593 and 21345602.

It is not an unprimeable number, because it can be changed into a prime (21345629) 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 59 ways as a sum of consecutive naturals, for example, 520605 + ... + 520645.

Almost surely, 2^21345625 is an apocalyptic number.

21345625 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21345625 is a deficient number, since it is larger than the sum of its proper divisors (12309227).

21345625 is an equidigital number, since it uses as much as digits as its factorization.

21345625 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 92 (or 70 counting only the distinct ones).

The product of its digits is 7200, while the sum is 28.

The square root of 21345625 is about 4620.1325738554. The cubic root of 21345625 is about 277.3977655488.

Adding to 21345625 its reverse (52654312), we get a palindrome (73999937).

The spelling of 21345625 in words is "twenty-one million, three hundred forty-five thousand, six hundred twenty-five".