91817849 has 2 divisors, whose sum is σ = 91817850. Its totient is φ = 91817848.

The previous prime is 91817827. The next prime is 91817851. The reversal of 91817849 is 94871819.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 82937449 + 8880400 = 9107^2 + 2980^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91817849 is a prime.

Together with 91817851, 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 (91817249) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45908924 + 45908925.

It is an arithmetic number, because the mean of its divisors is an integer number (45908925).

Almost surely, 2^91817849 is an apocalyptic number.

It is an amenable number.

91817849 is a deficient number, since it is larger than the sum of its proper divisors (1).

91817849 is an equidigital number, since it uses as much as digits as its factorization.

91817849 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 145152, while the sum is 47.

The square root of 91817849 is about 9582.1630647782. The cubic root of 91817849 is about 451.1376138348.

The spelling of 91817849 in words is "ninety-one million, eight hundred seventeen thousand, eight hundred forty-nine".