221161181 has 2 divisors, whose sum is σ = 221161182. Its totient is φ = 221161180.

The previous prime is 221161153. The next prime is 221161183. The reversal of 221161181 is 181161122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 210540100 + 10621081 = 14510^2 + 3259^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221161181 is a prime.

It is a super-2 number, since 2×221161181² = 97824535962629522, which contains 22 as substring.

Together with 221161183, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221161183) 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, 110580590 + 110580591.

It is an arithmetic number, because the mean of its divisors is an integer number (110580591).

Almost surely, 2^221161181 is an apocalyptic number.

It is an amenable number.

221161181 is a deficient number, since it is larger than the sum of its proper divisors (1).

221161181 is an equidigital number, since it uses as much as digits as its factorization.

221161181 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 192, while the sum is 23.

The square root of 221161181 is about 14871.4888629216. The cubic root of 221161181 is about 604.7413059698.

The spelling of 221161181 in words is "two hundred twenty-one million, one hundred sixty-one thousand, one hundred eighty-one".