21227264 has 36 divisors (see below), whose sum is σ = 42666456. Its totient is φ = 10540032.

The previous prime is 21227257. The next prime is 21227267. The reversal of 21227264 is 46272212.

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 polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 72302 + ... + 72594.

Almost surely, 2^21227264 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21227264, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21333228).

21227264 is an abundant number, since it is smaller than the sum of its proper divisors (21439192).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21227264 is an equidigital number, since it uses as much as digits as its factorization.

21227264 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 592 (or 578 counting only the distinct ones).

The product of its digits is 2688, while the sum is 26.

The square root of 21227264 is about 4607.3055032199. The cubic root of 21227264 is about 276.8840935311.

Adding to 21227264 its reverse (46272212), we get a palindrome (67499476).

The spelling of 21227264 in words is "twenty-one million, two hundred twenty-seven thousand, two hundred sixty-four".