8181865 has 4 divisors (see below), whose sum is σ = 9818244. Its totient is φ = 6545488.

The previous prime is 8181851. The next prime is 8181871. The reversal of 8181865 is 5681818.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 2359296 + 5822569 = 1536^2 + 2413^2 .

It is a cyclic number.

It is not a de Polignac number, because 8181865 - 2¹¹ = 8179817 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 818182 + ... + 818191.

It is an arithmetic number, because the mean of its divisors is an integer number (2454561).

Almost surely, 2^8181865 is an apocalyptic number.

It is an amenable number.

8181865 is a deficient number, since it is larger than the sum of its proper divisors (1636379).

8181865 is a wasteful number, since it uses less digits than its factorization.

8181865 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1636378.

The product of its digits is 15360, while the sum is 37.

The square root of 8181865 is about 2860.3959516123. The cubic root of 8181865 is about 201.5042002133.

The spelling of 8181865 in words is "eight million, one hundred eighty-one thousand, eight hundred sixty-five".