81113832991 has 2 divisors, whose sum is σ = 81113832992. Its totient is φ = 81113832990.

The previous prime is 81113832983. The next prime is 81113833001. The reversal of 81113832991 is 19923831118.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 81113832991 - 2³ = 81113832983 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (81113832971) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40556916495 + 40556916496.

It is an arithmetic number, because the mean of its divisors is an integer number (40556916496).

Almost surely, 2^81113832991 is an apocalyptic number.

81113832991 is a deficient number, since it is larger than the sum of its proper divisors (1).

81113832991 is an equidigital number, since it uses as much as digits as its factorization.

81113832991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 93312, while the sum is 46.

The spelling of 81113832991 in words is "eighty-one billion, one hundred thirteen million, eight hundred thirty-two thousand, nine hundred ninety-one".