21005227 has 2 divisors, whose sum is σ = 21005228. Its totient is φ = 21005226.

The previous prime is 21005219. The next prime is 21005269. The reversal of 21005227 is 72250012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21005227 - 2³ = 21005219 is a prime.

It is a super-2 number, since 2×21005227² = 882439122643058, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21005297) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10502613 + 10502614.

It is an arithmetic number, because the mean of its divisors is an integer number (10502614).

Almost surely, 2^21005227 is an apocalyptic number.

21005227 is a deficient number, since it is larger than the sum of its proper divisors (1).

21005227 is an equidigital number, since it uses as much as digits as its factorization.

21005227 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 280, while the sum is 19.

The square root of 21005227 is about 4583.1459719280. The cubic root of 21005227 is about 275.9153060514.

Adding to 21005227 its reverse (72250012), we get a palindrome (93255239).

The spelling of 21005227 in words is "twenty-one million, five thousand, two hundred twenty-seven".