21425125 has 8 divisors (see below), whose sum is σ = 26738712. Its totient is φ = 17140000.

The previous prime is 21425099. The next prime is 21425147. The reversal of 21425125 is 52152412.

It can be written as a sum of positive squares in 4 ways, for example, as 329476 + 21095649 = 574^2 + 4593^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21425125 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21425096 and 21425105.

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, 85576 + ... + 85825.

It is an arithmetic number, because the mean of its divisors is an integer number (3342339).

Almost surely, 2^21425125 is an apocalyptic number.

21425125 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21425125 is a deficient number, since it is larger than the sum of its proper divisors (5313587).

21425125 is an equidigital number, since it uses as much as digits as its factorization.

21425125 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 171416 (or 171406 counting only the distinct ones).

The product of its digits is 800, while the sum is 22.

The square root of 21425125 is about 4628.7282270619. The cubic root of 21425125 is about 277.7417205049.

Adding to 21425125 its reverse (52152412), we get a palindrome (73577537).

The spelling of 21425125 in words is "twenty-one million, four hundred twenty-five thousand, one hundred twenty-five".