9991087 has 4 divisors (see below), whose sum is σ = 10578816. Its totient is φ = 9403360.

The previous prime is 9991067. The next prime is 9991123. The reversal of 9991087 is 7801999.

9991087 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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 9991087 - 2¹¹ = 9989039 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 (9991027) 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, 293839 + ... + 293872.

It is an arithmetic number, because the mean of its divisors is an integer number (2644704).

Almost surely, 2^9991087 is an apocalyptic number.

9991087 is a deficient number, since it is larger than the sum of its proper divisors (587729).

9991087 is a wasteful number, since it uses less digits than its factorization.

9991087 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 587728.

The product of its (nonzero) digits is 40824, while the sum is 43.

The square root of 9991087 is about 3160.8680769687. The cubic root of 9991087 is about 215.3794417223.

The spelling of 9991087 in words is "nine million, nine hundred ninety-one thousand, eighty-seven".