20221018991 has 2 divisors, whose sum is σ = 20221018992. Its totient is φ = 20221018990.

The previous prime is 20221018981. The next prime is 20221019017. The reversal of 20221018991 is 19981012202.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 20221018991 - 2¹⁰ = 20221017967 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20221018901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10110509495 + 10110509496.

It is an arithmetic number, because the mean of its divisors is an integer number (10110509496).

Almost surely, 2^20221018991 is an apocalyptic number.

20221018991 is a deficient number, since it is larger than the sum of its proper divisors (1).

20221018991 is an equidigital number, since it uses as much as digits as its factorization.

20221018991 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5184, while the sum is 35.

The spelling of 20221018991 in words is "twenty billion, two hundred twenty-one million, eighteen thousand, nine hundred ninety-one".