91128577 has 2 divisors, whose sum is σ = 91128578. Its totient is φ = 91128576.

The previous prime is 91128523. The next prime is 91128637. The reversal of 91128577 is 77582119.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 48108096 + 43020481 = 6936^2 + 6559^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91128577 is a prime.

It is not a weakly prime, because it can be changed into another prime (91128377) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45564288 + 45564289.

It is an arithmetic number, because the mean of its divisors is an integer number (45564289).

Almost surely, 2^91128577 is an apocalyptic number.

It is an amenable number.

91128577 is a deficient number, since it is larger than the sum of its proper divisors (1).

91128577 is an equidigital number, since it uses as much as digits as its factorization.

91128577 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 35280, while the sum is 40.

The square root of 91128577 is about 9546.1289012877. The cubic root of 91128577 is about 450.0058879888.

It can be divided in two parts, 9112 and 8577, that added together give a square (17689 = 133²).

The spelling of 91128577 in words is "ninety-one million, one hundred twenty-eight thousand, five hundred seventy-seven".