21122112191 has 2 divisors, whose sum is σ = 21122112192. Its totient is φ = 21122112190.

The previous prime is 21122112149. The next prime is 21122112203. The reversal of 21122112191 is 19121122112.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21122112191 - 2¹⁰ = 21122111167 is a prime.

It is a super-2 number, since 2×21122112191² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21122112131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561056095 + 10561056096.

It is an arithmetic number, because the mean of its divisors is an integer number (10561056096).

Almost surely, 2^21122112191 is an apocalyptic number.

21122112191 is a deficient number, since it is larger than the sum of its proper divisors (1).

21122112191 is an equidigital number, since it uses as much as digits as its factorization.

21122112191 is an evil number, because the sum of its binary digits is even.

The product of its digits is 144, while the sum is 23.

The spelling of 21122112191 in words is "twenty-one billion, one hundred twenty-two million, one hundred twelve thousand, one hundred ninety-one".