91389181687 has 2 divisors, whose sum is σ = 91389181688. Its totient is φ = 91389181686.

The previous prime is 91389181673. The next prime is 91389181693. The reversal of 91389181687 is 78618198319.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 91389181687 - 2²³ = 91380793079 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91389181657) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45694590843 + 45694590844.

It is an arithmetic number, because the mean of its divisors is an integer number (45694590844).

Almost surely, 2^91389181687 is an apocalyptic number.

91389181687 is a deficient number, since it is larger than the sum of its proper divisors (1).

91389181687 is an equidigital number, since it uses as much as digits as its factorization.

91389181687 is an evil number, because the sum of its binary digits is even.

The product of its digits is 5225472, while the sum is 61.

The spelling of 91389181687 in words is "ninety-one billion, three hundred eighty-nine million, one hundred eighty-one thousand, six hundred eighty-seven".