21425265 has 24 divisors (see below), whose sum is σ = 37372608. Its totient is φ = 11354400.

The previous prime is 21425251. The next prime is 21425269. The reversal of 21425265 is 56252412.

It is not a de Polignac number, because 21425265 - 2⁵ = 21425233 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21425269) 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 23 ways as a sum of consecutive naturals, for example, 6090 + ... + 8940.

It is an arithmetic number, because the mean of its divisors is an integer number (1557192).

Almost surely, 2^21425265 is an apocalyptic number.

It is an amenable number.

21425265 is a deficient number, since it is larger than the sum of its proper divisors (15947343).

21425265 is a wasteful number, since it uses less digits than its factorization.

21425265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3029 (or 3026 counting only the distinct ones).

The product of its digits is 4800, while the sum is 27.

The square root of 21425265 is about 4628.7433499817. The cubic root of 21425265 is about 277.7423254607.

Adding to 21425265 its reverse (56252412), we get a palindrome (77677677).

The spelling of 21425265 in words is "twenty-one million, four hundred twenty-five thousand, two hundred sixty-five".