311109221 has 2 divisors, whose sum is σ = 311109222. Its totient is φ = 311109220.

The previous prime is 311109199. The next prime is 311109223. The reversal of 311109221 is 122901113.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 305865121 + 5244100 = 17489^2 + 2290^2 .

It is a cyclic number.

It is not a de Polignac number, because 311109221 - 2¹⁸ = 310847077 is a prime.

Together with 311109223, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 311109193 and 311109202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (311109223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 155554610 + 155554611.

It is an arithmetic number, because the mean of its divisors is an integer number (155554611).

Almost surely, 2^311109221 is an apocalyptic number.

It is an amenable number.

311109221 is a deficient number, since it is larger than the sum of its proper divisors (1).

311109221 is an equidigital number, since it uses as much as digits as its factorization.

311109221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108, while the sum is 20.

The square root of 311109221 is about 17638.2884940688. The cubic root of 311109221 is about 677.5961989914.

It can be divided in two parts, 3111092 and 21, that added together give a palindrome (3111113).

The spelling of 311109221 in words is "three hundred eleven million, one hundred nine thousand, two hundred twenty-one".