21663227 has 2 divisors, whose sum is σ = 21663228. Its totient is φ = 21663226.

The previous prime is 21663209. The next prime is 21663247. The reversal of 21663227 is 72236612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21663227 - 2¹⁰ = 21662203 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21663227.

It is not a weakly prime, because it can be changed into another prime (21663247) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10831613 + 10831614.

It is an arithmetic number, because the mean of its divisors is an integer number (10831614).

Almost surely, 2^21663227 is an apocalyptic number.

21663227 is a deficient number, since it is larger than the sum of its proper divisors (1).

21663227 is an equidigital number, since it uses as much as digits as its factorization.

21663227 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 6048, while the sum is 29.

The square root of 21663227 is about 4654.3771871218. The cubic root of 21663227 is about 278.7668002503.

Adding to 21663227 its reverse (72236612), we get a palindrome (93899839).

The spelling of 21663227 in words is "twenty-one million, six hundred sixty-three thousand, two hundred twenty-seven".