181820101091 has 2 divisors, whose sum is σ = 181820101092. Its totient is φ = 181820101090.

The previous prime is 181820101087. The next prime is 181820101117. The reversal of 181820101091 is 190101028181.

It is a weak prime.

It is an emirp because it is prime and its reverse (190101028181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 181820101091 - 2² = 181820101087 is a prime.

It is a Sophie Germain prime.

It is not a weakly prime, because it can be changed into another prime (181820101291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90910050545 + 90910050546.

It is an arithmetic number, because the mean of its divisors is an integer number (90910050546).

Almost surely, 2^181820101091 is an apocalyptic number.

181820101091 is a deficient number, since it is larger than the sum of its proper divisors (1).

181820101091 is an equidigital number, since it uses as much as digits as its factorization.

181820101091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152, while the sum is 32.

The spelling of 181820101091 in words is "one hundred eighty-one billion, eight hundred twenty million, one hundred one thousand, ninety-one".