9991787560 has 32 divisors (see below), whose sum is σ = 22598024040. Its totient is φ = 3976003584.

The previous prime is 9991787557. The next prime is 9991787569. The reversal of 9991787560 is 657871999.

It can be written as a sum of positive squares in 4 ways, for example, as 4251300804 + 5740486756 = 65202^2 + 75766^2 .

It is not an unprimeable number, because it can be changed into a prime (9991787569) 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, 639417 + ... + 654856.

Almost surely, 2^9991787560 is an apocalyptic number.

It is an amenable number.

9991787560 is an abundant number, since it is smaller than the sum of its proper divisors (12606236480).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

9991787560 is a wasteful number, since it uses less digits than its factorization.

9991787560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1294477 (or 1294473 counting only the distinct ones).

The product of its (nonzero) digits is 8573040, while the sum is 61.

The square root of 9991787560 is about 99958.9293660151. The cubic root of 9991787560 is about 2153.8447563217.

The spelling of 9991787560 in words is "nine billion, nine hundred ninety-one million, seven hundred eighty-seven thousand, five hundred sixty".