21225265 has 16 divisors (see below), whose sum is σ = 27378432. Its totient is φ = 15738624.

The previous prime is 21225263. The next prime is 21225277. The reversal of 21225265 is 56252212.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 21225265 - 2¹ = 21225263 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21225263) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3832 + ... + 7558.

It is an arithmetic number, because the mean of its divisors is an integer number (1711152).

Almost surely, 2^21225265 is an apocalyptic number.

It is an amenable number.

21225265 is a deficient number, since it is larger than the sum of its proper divisors (6153167).

21225265 is a wasteful number, since it uses less digits than its factorization.

21225265 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3816.

The product of its digits is 2400, while the sum is 25.

The square root of 21225265 is about 4607.0885600344. The cubic root of 21225265 is about 276.8754017424.

Adding to 21225265 its reverse (56252212), we get a palindrome (77477477).

The spelling of 21225265 in words is "twenty-one million, two hundred twenty-five thousand, two hundred sixty-five".