91857481 has 2 divisors, whose sum is σ = 91857482. Its totient is φ = 91857480.

The previous prime is 91857473. The next prime is 91857497. The reversal of 91857481 is 18475819.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 57153600 + 34703881 = 7560^2 + 5891^2 .

It is a cyclic number.

It is not a de Polignac number, because 91857481 - 2³ = 91857473 is a prime.

It is a super-2 number, since 2×91857481² = 16875593631330722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (91857401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45928740 + 45928741.

It is an arithmetic number, because the mean of its divisors is an integer number (45928741).

Almost surely, 2^91857481 is an apocalyptic number.

It is an amenable number.

91857481 is a deficient number, since it is larger than the sum of its proper divisors (1).

91857481 is an equidigital number, since it uses as much as digits as its factorization.

91857481 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 80640, while the sum is 43.

The square root of 91857481 is about 9584.2308507256. The cubic root of 91857481 is about 451.2025137580.

The spelling of 91857481 in words is "ninety-one million, eight hundred fifty-seven thousand, four hundred eighty-one".