8181000 has 160 divisors (see below), whose sum is σ = 28880280. Its totient is φ = 2160000.

The previous prime is 8180989. The next prime is 8181007. The reversal of 8181000 is 1818.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 4743684 + 3437316 = 2178^2 + 1854^2 .

It is a super-2 number, since 2×8181000² = 133857522000000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is not an unprimeable number, because it can be changed into a prime (8181007) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 80950 + ... + 81050.

Almost surely, 2^8181000 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 8181000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (14440140).

8181000 is an abundant number, since it is smaller than the sum of its proper divisors (20699280).

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

8181000 is a wasteful number, since it uses less digits than its factorization.

8181000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 134 (or 111 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 8181000 is about 2860.2447447727. The cubic root of 8181000 is about 201.4970988464.

Adding to 8181000 its reverse (1818), we get a palindrome (8182818).

The spelling of 8181000 in words is "eight million, one hundred eighty-one thousand".