991040 has 56 divisors (see below), whose sum is σ = 2499360. Its totient is φ = 373248.

The previous prime is 991037. The next prime is 991043. The reversal of 991040 is 40199.

991040 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (991037) and next prime (991043).

It is a junction number, because it is equal to n+sod(n) for n = 990997 and 991015.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991043) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5999 + ... + 6161.

2⁹⁹¹⁰⁴⁰ 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 991040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1249680).

991040 is an abundant number, since it is smaller than the sum of its proper divisors (1508320).

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

991040 is a wasteful number, since it uses less digits than its factorization.

991040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 199 (or 189 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 23.

The square root of 991040 is about 995.5099195890. The cubic root of 991040 is about 99.7004368486.

The spelling of 991040 in words is "nine hundred ninety-one thousand, forty".