221911211 has 2 divisors, whose sum is σ = 221911212. Its totient is φ = 221911210.

The previous prime is 221911189. The next prime is 221911231. The reversal of 221911211 is 112119122.

221911211 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an a-pointer prime, because the next prime (221911231) can be obtained adding 221911211 to its sum of digits (20).

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-221911211 is a prime.

It is not a weakly prime, because it can be changed into another prime (221911231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110955605 + 110955606.

It is an arithmetic number, because the mean of its divisors is an integer number (110955606).

Almost surely, 2^221911211 is an apocalyptic number.

221911211 is a deficient number, since it is larger than the sum of its proper divisors (1).

221911211 is an equidigital number, since it uses as much as digits as its factorization.

221911211 is an evil number, because the sum of its binary digits is even.

The product of its digits is 72, while the sum is 20.

The square root of 221911211 is about 14896.6845640230. The cubic root of 221911211 is about 605.4241599017.

The spelling of 221911211 in words is "two hundred twenty-one million, nine hundred eleven thousand, two hundred eleven".