7981818 has 32 divisors (see below), whose sum is σ = 17751552. Its totient is φ = 2376000.

The previous prime is 7981817. The next prime is 7981819. The reversal of 7981818 is 8181897.

It is an interprime number because it is at equal distance from previous prime (7981817) and next prime (7981819).

7981818 is a modest number, since divided by 1818 gives 798 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 7981818.

It is not an unprimeable number, because it can be changed into a prime (7981811) 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, 768 + ... + 4068.

It is an arithmetic number, because the mean of its divisors is an integer number (554736).

Almost surely, 2^7981818 is an apocalyptic number.

7981818 is a gapful number since it is divisible by the number (78) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 7981818, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8875776).

7981818 is an abundant number, since it is smaller than the sum of its proper divisors (9769734).

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

7981818 is a wasteful number, since it uses less digits than its factorization.

7981818 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3350.

The product of its digits is 32256, while the sum is 42.

The square root of 7981818 is about 2825.2111425520. The cubic root of 7981818 is about 199.8483684017.

The spelling of 7981818 in words is "seven million, nine hundred eighty-one thousand, eight hundred eighteen".