8507991 has 16 divisors (see below), whose sum is σ = 12355200. Its totient is φ = 5187168.

The previous prime is 8507959. The next prime is 8508011. The reversal of 8507991 is 1997058.

It is a happy number.

It is not a de Polignac number, because 8507991 - 2⁵ = 8507959 is a prime.

8507991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8507911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 921 + ... + 4226.

It is an arithmetic number, because the mean of its divisors is an integer number (772200).

Almost surely, 2^8507991 is an apocalyptic number.

8507991 is a deficient number, since it is larger than the sum of its proper divisors (3847209).

8507991 is a wasteful number, since it uses less digits than its factorization.

8507991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5198.

The product of its (nonzero) digits is 22680, while the sum is 39.

The square root of 8507991 is about 2916.8460706729. The cubic root of 8507991 is about 204.1466889981.

The spelling of 8507991 in words is "eight million, five hundred seven thousand, nine hundred ninety-one".