21111222091 has 2 divisors, whose sum is σ = 21111222092. Its totient is φ = 21111222090.

The previous prime is 21111222049. The next prime is 21111222113. The reversal of 21111222091 is 19022211112.

It is an a-pointer prime, because the next prime (21111222113) can be obtained adding 21111222091 to its sum of digits (22).

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21111222091 - 2²³ = 21102833483 is a prime.

It is not a weakly prime, because it can be changed into another prime (21111222991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10555611045 + 10555611046.

It is an arithmetic number, because the mean of its divisors is an integer number (10555611046).

Almost surely, 2^21111222091 is an apocalyptic number.

21111222091 is a deficient number, since it is larger than the sum of its proper divisors (1).

21111222091 is an equidigital number, since it uses as much as digits as its factorization.

21111222091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 144, while the sum is 22.

The spelling of 21111222091 in words is "twenty-one billion, one hundred eleven million, two hundred twenty-two thousand, ninety-one".