91691729 has 2 divisors, whose sum is σ = 91691730. Its totient is φ = 91691728.

The previous prime is 91691687. The next prime is 91691737. The reversal of 91691729 is 92719619.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 87928129 + 3763600 = 9377^2 + 1940^2 .

It is an emirp because it is prime and its reverse (92719619) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 91691729 - 2¹⁶ = 91626193 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 91691729.

It is not a weakly prime, because it can be changed into another prime (91691759) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 45845864 + 45845865.

It is an arithmetic number, because the mean of its divisors is an integer number (45845865).

Almost surely, 2^91691729 is an apocalyptic number.

It is an amenable number.

91691729 is a deficient number, since it is larger than the sum of its proper divisors (1).

91691729 is an equidigital number, since it uses as much as digits as its factorization.

91691729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 61236, while the sum is 44.

The square root of 91691729 is about 9575.5798257860. The cubic root of 91691729 is about 450.9309599448.

The spelling of 91691729 in words is "ninety-one million, six hundred ninety-one thousand, seven hundred twenty-nine".