8181813 has 16 divisors (see below), whose sum is σ = 11450880.
Its totient is φ = 5186544.
The previous prime is 8181809. The next prime is 8181821. The reversal of 8181813 is 3181818.
It is not a de Polignac number, because 8181813 - 22 = 8181809 is a prime.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (8181893) by changing a digit.
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 15 ways as a sum of consecutive naturals, for example, 19318 + ... + 19736.
It is an arithmetic number, because the mean of its divisors is an integer number (715680).
Almost surely, 28181813 is an apocalyptic number.
It is an amenable number.
8181813 is a deficient number, since it is larger than the sum of its proper divisors (3269067).
8181813 is a wasteful number, since it uses less digits than its factorization.
8181813 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 728.
The product of its digits is 1536, while the sum is 30.
The square root of 8181813 is about 2860.3868619472.
The cubic root of 8181813 is about 201.5037733245.
The spelling of 8181813 in words is "eight million, one hundred eighty-one thousand, eight hundred thirteen".