217111121 has 2 divisors, whose sum is σ = 217111122. Its totient is φ = 217111120.

The previous prime is 217111109. The next prime is 217111133. The reversal of 217111121 is 121111712.

217111121 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a balanced prime because it is at equal distance from previous prime (217111109) and next prime (217111133).

It can be written as a sum of positive squares in only one way, i.e., 130416400 + 86694721 = 11420^2 + 9311^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-217111121 is a 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 217111121.

It is not a weakly prime, because it can be changed into another prime (217111621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108555560 + 108555561.

It is an arithmetic number, because the mean of its divisors is an integer number (108555561).

Almost surely, 2^217111121 is an apocalyptic number.

It is an amenable number.

217111121 is a deficient number, since it is larger than the sum of its proper divisors (1).

217111121 is an equidigital number, since it uses as much as digits as its factorization.

217111121 is an evil number, because the sum of its binary digits is even.

The product of its digits is 28, while the sum is 17.

The square root of 217111121 is about 14734.6910724318. The cubic root of 217111121 is about 601.0270566620.

Adding to 217111121 its reverse (121111712), we get a palindrome (338222833).

The spelling of 217111121 in words is "two hundred seventeen million, one hundred eleven thousand, one hundred twenty-one".