21012227 has 2 divisors, whose sum is σ = 21012228. Its totient is φ = 21012226.

The previous prime is 21012193. The next prime is 21012239. The reversal of 21012227 is 72221012.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21012227 is a prime.

It is not a weakly prime, because it can be changed into another prime (21012127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506113 + 10506114.

It is an arithmetic number, because the mean of its divisors is an integer number (10506114).

Almost surely, 2^21012227 is an apocalyptic number.

21012227 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012227 is an equidigital number, since it uses as much as digits as its factorization.

21012227 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 112, while the sum is 17.

The square root of 21012227 is about 4583.9095758970. The cubic root of 21012227 is about 275.9459522747.

Adding to 21012227 its reverse (72221012), we get a palindrome (93233239).

The spelling of 21012227 in words is "twenty-one million, twelve thousand, two hundred twenty-seven".