961571685591 has 32 divisors (see below), whose sum is σ = 1555192742400. Its totient is φ = 582344159040.

The previous prime is 961571685509. The next prime is 961571685611. The reversal of 961571685591 is 195586175169.

961571685591 is a `hidden beast` number, since 9 + 6 + 1 + 5 + 71 + 6 + 8 + 559 + 1 = 666.

It is not a de Polignac number, because 961571685591 - 2³⁵ = 927211947223 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (961571685391) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 778206 + ... + 1590203.

It is an arithmetic number, because the mean of its divisors is an integer number (48599773200).

Almost surely, 2^961571685591 is an apocalyptic number.

961571685591 is a deficient number, since it is larger than the sum of its proper divisors (593621056809).

961571685591 is a wasteful number, since it uses less digits than its factorization.

961571685591 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2369796 (or 2369790 counting only the distinct ones).

The product of its digits is 20412000, while the sum is 63.

The spelling of 961571685591 in words is "nine hundred sixty-one billion, five hundred seventy-one million, six hundred eighty-five thousand, five hundred ninety-one".