91745881 has 2 divisors, whose sum is σ = 91745882. Its totient is φ = 91745880.

The previous prime is 91745869. The next prime is 91745887. The reversal of 91745881 is 18854719.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 69806025 + 21939856 = 8355^2 + 4684^2 .

It is a cyclic number.

It is not a de Polignac number, because 91745881 - 2⁹ = 91745369 is a prime.

It is a super-2 number, since 2×91745881² = 16834613360932322, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (91745887) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45872940 + 45872941.

It is an arithmetic number, because the mean of its divisors is an integer number (45872941).

Almost surely, 2^91745881 is an apocalyptic number.

It is an amenable number.

91745881 is a deficient number, since it is larger than the sum of its proper divisors (1).

91745881 is an equidigital number, since it uses as much as digits as its factorization.

91745881 is an evil number, because the sum of its binary digits is even.

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

The square root of 91745881 is about 9578.4070178710. The cubic root of 91745881 is about 451.0197138889.

The spelling of 91745881 in words is "ninety-one million, seven hundred forty-five thousand, eight hundred eighty-one".