91781752805 has 16 divisors (see below), whose sum is σ = 113753412720. Its totient is φ = 71053152768.

The previous prime is 91781752771. The next prime is 91781752807. The reversal of 91781752805 is 50825718719.

It can be written as a sum of positive squares in 8 ways, for example, as 10680395716 + 81101357089 = 103346^2 + 284783^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-91781752805 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (53).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (91781752807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2352890 + ... + 2391579.

It is an arithmetic number, because the mean of its divisors is an integer number (7109588295).

Almost surely, 2^91781752805 is an apocalyptic number.

It is an amenable number.

91781752805 is a deficient number, since it is larger than the sum of its proper divisors (21971659915).

91781752805 is a wasteful number, since it uses less digits than its factorization.

91781752805 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4744600.

The product of its (nonzero) digits is 1411200, while the sum is 53.

The spelling of 91781752805 in words is "ninety-one billion, seven hundred eighty-one million, seven hundred fifty-two thousand, eight hundred five".