91129221 has 6 divisors (see below), whose sum is σ = 131631110. Its totient is φ = 60752808.

The previous prime is 91129211. The next prime is 91129229. The reversal of 91129221 is 12292119.

It can be written as a sum of positive squares in only one way, i.e., 84824100 + 6305121 = 9210^2 + 2511^2 .

It is not a de Polignac number, because 91129221 - 2²³ = 82740613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91129229) 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 in 5 ways as a sum of consecutive naturals, for example, 5062726 + ... + 5062743.

Almost surely, 2^91129221 is an apocalyptic number.

It is an amenable number.

91129221 is a deficient number, since it is larger than the sum of its proper divisors (40501889).

91129221 is a wasteful number, since it uses less digits than its factorization.

91129221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10125475 (or 10125472 counting only the distinct ones).

The product of its digits is 648, while the sum is 27.

The square root of 91129221 is about 9546.1626321784. The cubic root of 91129221 is about 450.0069480409.

The spelling of 91129221 in words is "ninety-one million, one hundred twenty-nine thousand, two hundred twenty-one".