91666666787 has 2 divisors, whose sum is σ = 91666666788. Its totient is φ = 91666666786.

The previous prime is 91666666711. The next prime is 91666666789. The reversal of 91666666787 is 78766666619.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 91666666787 - 2¹⁰ = 91666665763 is a prime.

Together with 91666666789, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (91666666789) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45833333393 + 45833333394.

It is an arithmetic number, because the mean of its divisors is an integer number (45833333394).

Almost surely, 2^91666666787 is an apocalyptic number.

91666666787 is a deficient number, since it is larger than the sum of its proper divisors (1).

91666666787 is an equidigital number, since it uses as much as digits as its factorization.

91666666787 is an evil number, because the sum of its binary digits is even.

The product of its digits is 164602368, while the sum is 68.

The spelling of 91666666787 in words is "ninety-one billion, six hundred sixty-six million, six hundred sixty-six thousand, seven hundred eighty-seven".