9991008 has 72 divisors (see below), whose sum is σ = 28756728. Its totient is φ = 3290112.

The previous prime is 9990997. The next prime is 9991027. The reversal of 9991008 is 8001999.

It is a tau number, because it is divible by the number of its divisors (72).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 32391 + ... + 32697.

It is an arithmetic number, because the mean of its divisors is an integer number (399399).

Almost surely, 2^9991008 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 9991008, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14378364).

9991008 is an abundant number, since it is smaller than the sum of its proper divisors (18765720).

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

9991008 is a wasteful number, since it uses less digits than its factorization.

9991008 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 436 (or 425 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 36.

The square root of 9991008 is about 3160.8555803769. The cubic root of 9991008 is about 215.3788740489.

The spelling of 9991008 in words is "nine million, nine hundred ninety-one thousand, eight".