91681771 has 2 divisors, whose sum is σ = 91681772. Its totient is φ = 91681770.

The previous prime is 91681763. The next prime is 91681801. The reversal of 91681771 is 17718619.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 91681771 - 2³ = 91681763 is a prime.

It is not a weakly prime, because it can be changed into another prime (91681721) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45840885 + 45840886.

It is an arithmetic number, because the mean of its divisors is an integer number (45840886).

Almost surely, 2^91681771 is an apocalyptic number.

91681771 is a deficient number, since it is larger than the sum of its proper divisors (1).

91681771 is an equidigital number, since it uses as much as digits as its factorization.

91681771 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 21168, while the sum is 40.

The square root of 91681771 is about 9575.0598431550. The cubic root of 91681771 is about 450.9146351970.

The spelling of 91681771 in words is "ninety-one million, six hundred eighty-one thousand, seven hundred seventy-one".