7991040 has 72 divisors (see below), whose sum is σ = 25533648. Its totient is φ = 2129920.

The previous prime is 7991033. The next prime is 7991047. The reversal of 7991040 is 401997.

It is an interprime number because it is at equal distance from previous prime (7991033) and next prime (7991047).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 7990989 and 7991007.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (7991047) 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, 2800 + ... + 4880.

It is an arithmetic number, because the mean of its divisors is an integer number (354634).

Almost surely, 2^7991040 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 7991040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12766824).

7991040 is an abundant number, since it is smaller than the sum of its proper divisors (17542608).

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

7991040 is a wasteful number, since it uses less digits than its factorization.

7991040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2105 (or 2091 counting only the distinct ones).

The product of its (nonzero) digits is 2268, while the sum is 30.

The square root of 7991040 is about 2826.8427618104. The cubic root of 7991040 is about 199.9253054404.

It can be divided in two parts, 79 and 91040, that added together give a palindrome (91119).

The spelling of 7991040 in words is "seven million, nine hundred ninety-one thousand, forty".