221717231 has 2 divisors, whose sum is σ = 221717232. Its totient is φ = 221717230.

The previous prime is 221717219. The next prime is 221717261. The reversal of 221717231 is 132717122.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221717231 - 2²² = 217522927 is a prime.

It is a super-2 number, since 2×221717231² = 98317061044614722, which contains 22 as substring.

It is a Sophie Germain 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 221717231.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221717201) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110858615 + 110858616.

It is an arithmetic number, because the mean of its divisors is an integer number (110858616).

Almost surely, 2^221717231 is an apocalyptic number.

221717231 is a deficient number, since it is larger than the sum of its proper divisors (1).

221717231 is an equidigital number, since it uses as much as digits as its factorization.

221717231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1176, while the sum is 26.

The square root of 221717231 is about 14890.1722958467. The cubic root of 221717231 is about 605.2477013171.

The spelling of 221717231 in words is "two hundred twenty-one million, seven hundred seventeen thousand, two hundred thirty-one".