91216281 has 16 divisors (see below), whose sum is σ = 135495360. Its totient is φ = 54196800.

The previous prime is 91216273. The next prime is 91216297. The reversal of 91216281 is 18261219.

It is a happy number.

It is not a de Polignac number, because 91216281 - 2³ = 91216273 is a prime.

It is a super-2 number, since 2×91216281² = 16640819838941922, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (91216241) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 39195 + ... + 41456.

It is an arithmetic number, because the mean of its divisors is an integer number (8468460).

Almost surely, 2^91216281 is an apocalyptic number.

It is an amenable number.

91216281 is a deficient number, since it is larger than the sum of its proper divisors (44279079).

91216281 is a wasteful number, since it uses less digits than its factorization.

91216281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 80696.

The product of its digits is 1728, while the sum is 30.

The square root of 91216281 is about 9550.7214910707. The cubic root of 91216281 is about 450.1502066467.

The spelling of 91216281 in words is "ninety-one million, two hundred sixteen thousand, two hundred eighty-one".