91081777 has 2 divisors, whose sum is σ = 91081778. Its totient is φ = 91081776.

The previous prime is 91081759. The next prime is 91081789. The reversal of 91081777 is 77718019.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 83247376 + 7834401 = 9124^2 + 2799^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91081777 is a prime.

It is not a weakly prime, because it can be changed into another prime (91081477) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45540888 + 45540889.

It is an arithmetic number, because the mean of its divisors is an integer number (45540889).

Almost surely, 2^91081777 is an apocalyptic number.

It is an amenable number.

91081777 is a deficient number, since it is larger than the sum of its proper divisors (1).

91081777 is an equidigital number, since it uses as much as digits as its factorization.

91081777 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24696, while the sum is 40.

The square root of 91081777 is about 9543.6773310920. The cubic root of 91081777 is about 449.9288397766.

The spelling of 91081777 in words is "ninety-one million, eighty-one thousand, seven hundred seventy-seven".