181401327297991 has 2 divisors, whose sum is σ = 181401327297992. Its totient is φ = 181401327297990.

The previous prime is 181401327297989. The next prime is 181401327298003. The reversal of 181401327297991 is 199792723104181.

It is a weak prime.

It is an emirp because it is prime and its reverse (199792723104181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 181401327297991 - 2¹ = 181401327297989 is a prime.

Together with 181401327297989, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (181401367297991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90700663648995 + 90700663648996.

It is an arithmetic number, because the mean of its divisors is an integer number (90700663648996).

Almost surely, 2^{181401327297991} is an apocalyptic number.

181401327297991 is a deficient number, since it is larger than the sum of its proper divisors (1).

181401327297991 is an equidigital number, since it uses as much as digits as its factorization.

181401327297991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13716864, while the sum is 64.

The spelling of 181401327297991 in words is "one hundred eighty-one trillion, four hundred one billion, three hundred twenty-seven million, two hundred ninety-seven thousand, nine hundred ninety-one".