221643271 has 2 divisors, whose sum is σ = 221643272. Its totient is φ = 221643270.

The previous prime is 221643221. The next prime is 221643277. The reversal of 221643271 is 172346122.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 221643271 - 2¹⁷ = 221512199 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221643277) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110821635 + 110821636.

It is an arithmetic number, because the mean of its divisors is an integer number (110821636).

Almost surely, 2^221643271 is an apocalyptic number.

221643271 is a deficient number, since it is larger than the sum of its proper divisors (1).

221643271 is an equidigital number, since it uses as much as digits as its factorization.

221643271 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032, while the sum is 28.

The square root of 221643271 is about 14887.6885714338. The cubic root of 221643271 is about 605.1803947180.

Adding to 221643271 its reverse (172346122), we get a palindrome (393989393).

The spelling of 221643271 in words is "two hundred twenty-one million, six hundred forty-three thousand, two hundred seventy-one".