91322765521 has 8 divisors (see below), whose sum is σ = 99452624040. Its totient is φ = 83350768512.

The previous prime is 91322765509. The next prime is 91322765531. The reversal of 91322765521 is 12556722319.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 10575859921 + 80746905600 = 102839^2 + 284160^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 91322765521 - 2¹¹ = 91322763473 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91322765531) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 39464170 + ... + 39466483.

It is an arithmetic number, because the mean of its divisors is an integer number (12431578005).

Almost surely, 2^91322765521 is an apocalyptic number.

It is an amenable number.

91322765521 is a deficient number, since it is larger than the sum of its proper divisors (8129858519).

91322765521 is a wasteful number, since it uses less digits than its factorization.

91322765521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 78930755.

The product of its digits is 226800, while the sum is 43.

The spelling of 91322765521 in words is "ninety-one billion, three hundred twenty-two million, seven hundred sixty-five thousand, five hundred twenty-one".