91126721 has 12 divisors (see below), whose sum is σ = 106189632. Its totient is φ = 77972328.

The previous prime is 91126699. The next prime is 91126733. The reversal of 91126721 is 12762119.

It is not a de Polignac number, because 91126721 - 2¹⁸ = 90864577 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (91126781) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 35156 + ... + 37658.

It is an arithmetic number, because the mean of its divisors is an integer number (8849136).

Almost surely, 2^91126721 is an apocalyptic number.

It is an amenable number.

91126721 is a deficient number, since it is larger than the sum of its proper divisors (15062911).

91126721 is a wasteful number, since it uses less digits than its factorization.

91126721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3260 (or 3253 counting only the distinct ones).

The product of its digits is 1512, while the sum is 29.

The square root of 91126721 is about 9546.0316886128. The cubic root of 91126721 is about 450.0028329040.

The spelling of 91126721 in words is "ninety-one million, one hundred twenty-six thousand, seven hundred twenty-one".