81375058991 has 2 divisors, whose sum is σ = 81375058992. Its totient is φ = 81375058990.

The previous prime is 81375058967. The next prime is 81375059027. The reversal of 81375058991 is 19985057318.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-81375058991 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81375058591) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40687529495 + 40687529496.

It is an arithmetic number, because the mean of its divisors is an integer number (40687529496).

Almost surely, 2^81375058991 is an apocalyptic number.

81375058991 is a deficient number, since it is larger than the sum of its proper divisors (1).

81375058991 is an equidigital number, since it uses as much as digits as its factorization.

81375058991 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2721600, while the sum is 56.

The spelling of 81375058991 in words is "eighty-one billion, three hundred seventy-five million, fifty-eight thousand, nine hundred ninety-one".