221221222091 has 2 divisors, whose sum is σ = 221221222092. Its totient is φ = 221221222090.

The previous prime is 221221222051. The next prime is 221221222147. The reversal of 221221222091 is 190222122122.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 221221222091 - 2²⁶ = 221154113227 is a prime.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 221221222091.

It is not a weakly prime, because it can be changed into another prime (221221222031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110610611045 + 110610611046.

It is an arithmetic number, because the mean of its divisors is an integer number (110610611046).

Almost surely, 2^221221222091 is an apocalyptic number.

221221222091 is a deficient number, since it is larger than the sum of its proper divisors (1).

221221222091 is an equidigital number, since it uses as much as digits as its factorization.

221221222091 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 26.

The spelling of 221221222091 in words is "two hundred twenty-one billion, two hundred twenty-one million, two hundred twenty-two thousand, ninety-one".