91857797 has 2 divisors, whose sum is σ = 91857798. Its totient is φ = 91857796.

The previous prime is 91857793. The next prime is 91857859. The reversal of 91857797 is 79775819.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 63138916 + 28718881 = 7946^2 + 5359^2 .

It is an emirp because it is prime and its reverse (79775819) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91857797 - 2² = 91857793 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (91857793) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45928898 + 45928899.

It is an arithmetic number, because the mean of its divisors is an integer number (45928899).

Almost surely, 2^91857797 is an apocalyptic number.

It is an amenable number.

91857797 is a deficient number, since it is larger than the sum of its proper divisors (1).

91857797 is an equidigital number, since it uses as much as digits as its factorization.

91857797 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1111320, while the sum is 53.

The square root of 91857797 is about 9584.2473361240. The cubic root of 91857797 is about 451.2030311531.

The spelling of 91857797 in words is "ninety-one million, eight hundred fifty-seven thousand, seven hundred ninety-seven".