8181909 has 12 divisors (see below), whose sum is σ = 11936652. Its totient is φ = 5400000.

The previous prime is 8181893. The next prime is 8181917. The reversal of 8181909 is 9091818.

It can be written as a sum of positive squares in 2 ways, for example, as 5049009 + 3132900 = 2247^2 + 1770^2 .

It is not a de Polignac number, because 8181909 - 2⁴ = 8181893 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8181949) 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 11 ways as a sum of consecutive naturals, for example, 3592 + ... + 5409.

It is an arithmetic number, because the mean of its divisors is an integer number (994721).

Almost surely, 2^8181909 is an apocalyptic number.

It is an amenable number.

8181909 is a deficient number, since it is larger than the sum of its proper divisors (3754743).

8181909 is a wasteful number, since it uses less digits than its factorization.

8181909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9108 (or 9105 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 36.

The square root of 8181909 is about 2860.4036428448. The cubic root of 8181909 is about 201.5045614256.

Subtracting 8181909 from its reverse (9091818), we obtain a palindrome (909909).

It can be divided in two parts, 8181 and 909, that multiplied together give a square (7436529 = 2727²).

The spelling of 8181909 in words is "eight million, one hundred eighty-one thousand, nine hundred nine".