8081991 has 8 divisors (see below), whose sum is σ = 11973360. Its totient is φ = 5387976.

The previous prime is 8081971. The next prime is 8082013. The reversal of 8081991 is 1991808.

It is not a de Polignac number, because 8081991 - 2¹¹ = 8079943 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8081971) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 149640 + ... + 149693.

It is an arithmetic number, because the mean of its divisors is an integer number (1496670).

Almost surely, 2^8081991 is an apocalyptic number.

8081991 is a deficient number, since it is larger than the sum of its proper divisors (3891369).

8081991 is a wasteful number, since it uses less digits than its factorization.

8081991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 299342 (or 299336 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 36.

The square root of 8081991 is about 2842.8842748167. The cubic root of 8081991 is about 200.6809373240.

The spelling of 8081991 in words is "eight million, eighty-one thousand, nine hundred ninety-one".