91072116787 has 2 divisors, whose sum is σ = 91072116788. Its totient is φ = 91072116786.

The previous prime is 91072116731. The next prime is 91072116803. The reversal of 91072116787 is 78761127019.

It is a strong prime.

It is an emirp because it is prime and its reverse (78761127019) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91072116787 - 2¹¹ = 91072114739 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 91072116787.

It is not a weakly prime, because it can be changed into another prime (91072116587) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45536058393 + 45536058394.

It is an arithmetic number, because the mean of its divisors is an integer number (45536058394).

Almost surely, 2^91072116787 is an apocalyptic number.

91072116787 is a deficient number, since it is larger than the sum of its proper divisors (1).

91072116787 is an equidigital number, since it uses as much as digits as its factorization.

91072116787 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 296352, while the sum is 49.

The spelling of 91072116787 in words is "ninety-one billion, seventy-two million, one hundred sixteen thousand, seven hundred eighty-seven".