9811882991 has 4 divisors (see below), whose sum is σ = 9812906400. Its totient is φ = 9810859584.

The previous prime is 9811882957. The next prime is 9811883021. The reversal of 9811882991 is 1992881189.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 9811882991 - 2¹⁰ = 9811881967 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9811882901) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 497186 + ... + 516543.

It is an arithmetic number, because the mean of its divisors is an integer number (2453226600).

Almost surely, 2^9811882991 is an apocalyptic number.

9811882991 is a deficient number, since it is larger than the sum of its proper divisors (1023409).

9811882991 is a wasteful number, since it uses less digits than its factorization.

9811882991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1023408.

The product of its digits is 746496, while the sum is 56.

The square root of 9811882991 is about 99054.9493513575. The cubic root of 9811882991 is about 2140.8395540560.

The spelling of 9811882991 in words is "nine billion, eight hundred eleven million, eight hundred eighty-two thousand, nine hundred ninety-one".