91609713561 has 16 divisors (see below), whose sum is σ = 122551116480. Its totient is φ = 60870960960.

The previous prime is 91609713539. The next prime is 91609713683. The reversal of 91609713561 is 16531790619.

It is a happy number.

It is not a de Polignac number, because 91609713561 - 2²¹ = 91607616409 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 91609713561.

It is not an unprimeable number, because it can be changed into a prime (91609713361) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1583206 + ... + 1640048.

It is an arithmetic number, because the mean of its divisors is an integer number (7659444780).

Almost surely, 2^91609713561 is an apocalyptic number.

It is an amenable number.

91609713561 is a deficient number, since it is larger than the sum of its proper divisors (30941402919).

91609713561 is a wasteful number, since it uses less digits than its factorization.

91609713561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 58616.

The product of its (nonzero) digits is 306180, while the sum is 48.

The spelling of 91609713561 in words is "ninety-one billion, six hundred nine million, seven hundred thirteen thousand, five hundred sixty-one".