21351227 has 2 divisors, whose sum is σ = 21351228. Its totient is φ = 21351226.

The previous prime is 21351217. The next prime is 21351233. The reversal of 21351227 is 72215312.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21351227 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21351217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10675613 + 10675614.

It is an arithmetic number, because the mean of its divisors is an integer number (10675614).

Almost surely, 2^21351227 is an apocalyptic number.

21351227 is a deficient number, since it is larger than the sum of its proper divisors (1).

21351227 is an equidigital number, since it uses as much as digits as its factorization.

21351227 is an evil number, because the sum of its binary digits is even.

The product of its digits is 840, while the sum is 23.

The square root of 21351227 is about 4620.7387937428. The cubic root of 21351227 is about 277.4220304174.

Adding to 21351227 its reverse (72215312), we get a palindrome (93566539).

The spelling of 21351227 in words is "twenty-one million, three hundred fifty-one thousand, two hundred twenty-seven".