8921078991 has 32 divisors (see below), whose sum is σ = 14807596800. Its totient is φ = 5260580640.

The previous prime is 8921078989. The next prime is 8921079031. The reversal of 8921078991 is 1998701298.

It is not a de Polignac number, because 8921078991 - 2¹ = 8921078989 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8921078921) 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, 394921 + ... + 416898.

It is an arithmetic number, because the mean of its divisors is an integer number (462737400).

Almost surely, 2^8921078991 is an apocalyptic number.

8921078991 is a deficient number, since it is larger than the sum of its proper divisors (5886517809).

8921078991 is a wasteful number, since it uses less digits than its factorization.

8921078991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 811876 (or 811870 counting only the distinct ones).

The product of its (nonzero) digits is 653184, while the sum is 54.

The square root of 8921078991 is about 94451.4636784417. The cubic root of 8921078991 is about 2073.9858781621.

The spelling of 8921078991 in words is "eight billion, nine hundred twenty-one million, seventy-eight thousand, nine hundred ninety-one".