9891997800 has 48 divisors (see below), whose sum is σ = 30665195040. Its totient is φ = 2637865920.

The previous prime is 9891997727. The next prime is 9891997807. The reversal of 9891997800 is 87991989.

9891997800 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (60).

It is not an unprimeable number, because it can be changed into a prime (9891997807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 8242732 + ... + 8243931.

It is an arithmetic number, because the mean of its divisors is an integer number (638858230).

Almost surely, 2^9891997800 is an apocalyptic number.

It is an amenable number.

9891997800 is an abundant number, since it is smaller than the sum of its proper divisors (20773197240).

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

9891997800 is a wasteful number, since it uses less digits than its factorization.

9891997800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16486682 (or 16486673 counting only the distinct ones).

The product of its (nonzero) digits is 2939328, while the sum is 60.

The square root of 9891997800 is about 99458.5230133647. The cubic root of 9891997800 is about 2146.6504757897.

The spelling of 9891997800 in words is "nine billion, eight hundred ninety-one million, nine hundred ninety-seven thousand, eight hundred".