91005281 has 4 divisors (see below), whose sum is σ = 93224964. Its totient is φ = 88785600.

The previous prime is 91005263. The next prime is 91005289. The reversal of 91005281 is 18250019.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18250019 = 29 ⋅629311.

It can be written as a sum of positive squares in 2 ways, for example, as 45104656 + 45900625 = 6716^2 + 6775^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91005281 is a prime.

It is a super-2 number, since 2×91005281² = 16563922339777922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 91005281.

It is not an unprimeable number, because it can be changed into a prime (91005289) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1109780 + ... + 1109861.

It is an arithmetic number, because the mean of its divisors is an integer number (23306241).

Almost surely, 2^91005281 is an apocalyptic number.

It is an amenable number.

91005281 is a deficient number, since it is larger than the sum of its proper divisors (2219683).

91005281 is a wasteful number, since it uses less digits than its factorization.

91005281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2219682.

The product of its (nonzero) digits is 720, while the sum is 26.

The square root of 91005281 is about 9539.6688097648. The cubic root of 91005281 is about 449.8028453222.

The spelling of 91005281 in words is "ninety-one million, five thousand, two hundred eighty-one".