91608523561 has 9 divisors (see below), whose sum is σ = 92011319589. Its totient is φ = 91207487136.

The previous prime is 91608523549. The next prime is 91608523571. The reversal of 91608523561 is 16532580619.

The square root of 91608523561 is 302669.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 76296935961 + 15311587600 = 276219^2 + 123740^2 .

It is not a de Polignac number, because 91608523561 - 2¹⁵ = 91608490793 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (91608523571) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 88681501 + ... + 88682533.

Almost surely, 2^91608523561 is an apocalyptic number.

91608523561 is the 302669-th square number.

91608523561 is the 151335-th centered octagonal number.

It is an amenable number.

91608523561 is a deficient number, since it is larger than the sum of its proper divisors (402796028).

91608523561 is an frugal number, since it uses more digits than its factorization.

91608523561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2652 (or 1326 counting only the distinct ones).

The product of its (nonzero) digits is 388800, while the sum is 46.

The spelling of 91608523561 in words is "ninety-one billion, six hundred eight million, five hundred twenty-three thousand, five hundred sixty-one".