21618227 has 2 divisors, whose sum is σ = 21618228. Its totient is φ = 21618226.

The previous prime is 21618221. The next prime is 21618241. The reversal of 21618227 is 72281612.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21618227 - 2¹⁰ = 21617203 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 21618227.

It is not a weakly prime, because it can be changed into another prime (21618221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10809113 + 10809114.

It is an arithmetic number, because the mean of its divisors is an integer number (10809114).

Almost surely, 2^21618227 is an apocalyptic number.

21618227 is a deficient number, since it is larger than the sum of its proper divisors (1).

21618227 is an equidigital number, since it uses as much as digits as its factorization.

21618227 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2688, while the sum is 29.

The square root of 21618227 is about 4649.5405149326. The cubic root of 21618227 is about 278.5736433999.

Adding to 21618227 its reverse (72281612), we get a palindrome (93899839).

The spelling of 21618227 in words is "twenty-one million, six hundred eighteen thousand, two hundred twenty-seven".