21244425 has 24 divisors (see below), whose sum is σ = 35726880. Its totient is φ = 11136000.

The previous prime is 21244417. The next prime is 21244459. The reversal of 21244425 is 52444212.

It is a happy number.

It is not a de Polignac number, because 21244425 - 2³ = 21244417 is a prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21244395 and 21244404.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2025 + ... + 6825.

It is an arithmetic number, because the mean of its divisors is an integer number (1488620).

Almost surely, 2^21244425 is an apocalyptic number.

21244425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21244425 is a deficient number, since it is larger than the sum of its proper divisors (14482455).

21244425 is a wasteful number, since it uses less digits than its factorization.

21244425 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4873 (or 4868 counting only the distinct ones).

The product of its digits is 2560, while the sum is 24.

The square root of 21244425 is about 4609.1674953293. The cubic root of 21244425 is about 276.9586882919.

Adding to 21244425 its reverse (52444212), we get a palindrome (73688637).

The spelling of 21244425 in words is "twenty-one million, two hundred forty-four thousand, four hundred twenty-five".