21242425 has 12 divisors (see below), whose sum is σ = 26472016. Its totient is φ = 16909200.

The previous prime is 21242393. The next prime is 21242443. The reversal of 21242425 is 52424212.

It is not a de Polignac number, because 21242425 - 2⁵ = 21242393 is a prime.

It is a hoax number, since the sum of its digits (22) coincides with the sum of the digits of its distinct prime factors.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21242396 and 21242405.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3262 + ... + 7288.

Almost surely, 2^21242425 is an apocalyptic number.

21242425 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21242425 is a deficient number, since it is larger than the sum of its proper divisors (5229591).

21242425 is a wasteful number, since it uses less digits than its factorization.

21242425 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4248 (or 4243 counting only the distinct ones).

The product of its digits is 1280, while the sum is 22.

The square root of 21242425 is about 4608.9505313032. The cubic root of 21242425 is about 276.9499968389.

Adding to 21242425 its reverse (52424212), we get a palindrome (73666637).

The spelling of 21242425 in words is "twenty-one million, two hundred forty-two thousand, four hundred twenty-five".