991008 has 96 divisors (see below), whose sum is σ = 3064320. Its totient is φ = 311040.

The previous prime is 990989. The next prime is 991009. The reversal of 991008 is 800199.

991008 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (96).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 991008.

It is not an unprimeable number, because it can be changed into a prime (991009) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26766 + ... + 26802.

It is an arithmetic number, because the mean of its divisors is an integer number (31920).

2⁹⁹¹⁰⁰⁸ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1532160).

991008 is an abundant number, since it is smaller than the sum of its proper divisors (2073312).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

991008 is a wasteful number, since it uses less digits than its factorization.

991008 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87 (or 73 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 27.

The square root of 991008 is about 995.4938472939. The cubic root of 991008 is about 99.6993637509.

The spelling of 991008 in words is "nine hundred ninety-one thousand, eight".