21222571 has 8 divisors (see below), whose sum is σ = 22155824. Its totient is φ = 20308320.

The previous prime is 21222559. The next prime is 21222587. The reversal of 21222571 is 17522212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21222571 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21222371) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2445 + ... + 6958.

It is an arithmetic number, because the mean of its divisors is an integer number (2769478).

Almost surely, 2^21222571 is an apocalyptic number.

21222571 is a deficient number, since it is larger than the sum of its proper divisors (933253).

21222571 is an equidigital number, since it uses as much as digits as its factorization.

21222571 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9501.

The product of its digits is 560, while the sum is 22.

The square root of 21222571 is about 4606.7961752177. The cubic root of 21222571 is about 276.8636871829.

Adding to 21222571 its reverse (17522212), we get a palindrome (38744783).

The spelling of 21222571 in words is "twenty-one million, two hundred twenty-two thousand, five hundred seventy-one".