21226571 has 2 divisors, whose sum is σ = 21226572. Its totient is φ = 21226570.

The previous prime is 21226547. The next prime is 21226603. The reversal of 21226571 is 17562212.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21226571 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 21226571.

It is not a weakly prime, because it can be changed into another prime (21226511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10613285 + 10613286.

It is an arithmetic number, because the mean of its divisors is an integer number (10613286).

Almost surely, 2^21226571 is an apocalyptic number.

21226571 is a deficient number, since it is larger than the sum of its proper divisors (1).

21226571 is an equidigital number, since it uses as much as digits as its factorization.

21226571 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1680, while the sum is 26.

The square root of 21226571 is about 4607.2302959587. The cubic root of 21226571 is about 276.8810803815.

Adding to 21226571 its reverse (17562212), we get a palindrome (38788783).

The spelling of 21226571 in words is "twenty-one million, two hundred twenty-six thousand, five hundred seventy-one".