21425525 has 24 divisors (see below), whose sum is σ = 30694464. Its totient is φ = 14662400.

The previous prime is 21425501. The next prime is 21425533. The reversal of 21425525 is 52552412.

It is not a de Polignac number, because 21425525 - 2⁸ = 21425269 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21425494 and 21425503.

It is a congruent number.

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, 2384 + ... + 6966.

It is an arithmetic number, because the mean of its divisors is an integer number (1278936).

Almost surely, 2^21425525 is an apocalyptic number.

21425525 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

It is an amenable number.

21425525 is a deficient number, since it is larger than the sum of its proper divisors (9268939).

21425525 is a wasteful number, since it uses less digits than its factorization.

21425525 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4621 (or 4616 counting only the distinct ones).

The product of its digits is 4000, while the sum is 26.

The square root of 21425525 is about 4628.7714352731. The cubic root of 21425525 is about 277.7434489429.

Adding to 21425525 its reverse (52552412), we get a palindrome (73977937).

It can be divided in two parts, 2142 and 5525, that added together give a palindrome (7667).

The spelling of 21425525 in words is "twenty-one million, four hundred twenty-five thousand, five hundred twenty-five".