9005991 has 8 divisors (see below), whose sum is σ = 12085104. Its totient is φ = 5965440.

The previous prime is 9005989. The next prime is 9006013. The reversal of 9005991 is 1995009.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 9005991 - 2¹ = 9005989 is a prime.

It is a super-2 number, since 2×9005991² = 162215747784162, which contains 22 as substring.

9005991 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9004991) 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, 9090 + ... + 10031.

It is an arithmetic number, because the mean of its divisors is an integer number (1510638).

Almost surely, 2^9005991 is an apocalyptic number.

9005991 is a deficient number, since it is larger than the sum of its proper divisors (3079113).

9005991 is a wasteful number, since it uses less digits than its factorization.

9005991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19281.

The product of its (nonzero) digits is 3645, while the sum is 33.

The square root of 9005991 is about 3000.9983338882. The cubic root of 9005991 is about 208.0545268166.

The spelling of 9005991 in words is "nine million, five thousand, nine hundred ninety-one".