21227265 has 24 divisors (see below), whose sum is σ = 38158848. Its totient is φ = 11320560.

The previous prime is 21227257. The next prime is 21227267. The reversal of 21227265 is 56272212.

It is not a de Polignac number, because 21227265 - 2³ = 21227257 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21227267) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7521 + ... + 9950.

It is an arithmetic number, because the mean of its divisors is an integer number (1589952).

Almost surely, 2^21227265 is an apocalyptic number.

It is an amenable number.

21227265 is a deficient number, since it is larger than the sum of its proper divisors (16931583).

21227265 is an equidigital number, since it uses as much as digits as its factorization.

21227265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17491 (or 17479 counting only the distinct ones).

The product of its digits is 3360, while the sum is 27.

The square root of 21227265 is about 4607.3056117432. The cubic root of 21227265 is about 276.8840978790.

Adding to 21227265 its reverse (56272212), we get a palindrome (77499477).

The spelling of 21227265 in words is "twenty-one million, two hundred twenty-seven thousand, two hundred sixty-five".