21227564 has 12 divisors (see below), whose sum is σ = 37191000. Its totient is φ = 10601568.

The previous prime is 21227561. The next prime is 21227567. The reversal of 21227564 is 46572212.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21227561) and next prime (21227567).

It is not an unprimeable number, because it can be changed into a prime (21227561) 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 3 ways as a sum of consecutive naturals, for example, 1667 + ... + 6725.

It is an arithmetic number, because the mean of its divisors is an integer number (3099250).

Almost surely, 2^21227564 is an apocalyptic number.

It is an amenable number.

21227564 is a deficient number, since it is larger than the sum of its proper divisors (15963436).

21227564 is a wasteful number, since it uses less digits than its factorization.

21227564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6112 (or 6110 counting only the distinct ones).

The product of its digits is 6720, while the sum is 29.

The square root of 21227564 is about 4607.3380600950. The cubic root of 21227564 is about 276.8853979045.

Adding to 21227564 its reverse (46572212), we get a palindrome (67799776).

The spelling of 21227564 in words is "twenty-one million, two hundred twenty-seven thousand, five hundred sixty-four".