13218809 has 8 divisors (see below), whose sum is σ = 14479560. Its totient is φ = 12011776.

The previous prime is 13218743. The next prime is 13218823. The reversal of 13218809 is 90881231.

It can be written as a sum of positive squares in 4 ways, for example, as 5221225 + 7997584 = 2285^2 + 2828^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 13218809 - 2¹² = 13214713 is a prime.

It is a super-2 number, since 2×13218809² = 349473822756962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13218839) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12914 + ... + 13899.

It is an arithmetic number, because the mean of its divisors is an integer number (1809945).

Almost surely, 2^13218809 is an apocalyptic number.

It is an amenable number.

13218809 is a deficient number, since it is larger than the sum of its proper divisors (1260751).

13218809 is a wasteful number, since it uses less digits than its factorization.

13218809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26859.

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 13218809 is about 3635.7680069003. The cubic root of 13218809 is about 236.4453490970.

The spelling of 13218809 in words is "thirteen million, two hundred eighteen thousand, eight hundred nine".