11918699808409 has 9 divisors (see below), whose sum is σ = 11937188114271. Its totient is φ = 11900240109000.

The previous prime is 11918699808401. The next prime is 11918699808419. The reversal of 11918699808409 is 90480899681911.

The square root of 11918699808409 is 3452347.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 860228425225 + 11058471383184 = 927485^2 + 3325428^2 .

It is not a de Polignac number, because 11918699808409 - 2³ = 11918699808401 is a prime.

It is a super-2 number, since 2×11918699808409² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11918699808401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 2592710299 + ... + 2592714895.

It is an arithmetic number, because the mean of its divisors is an integer number (1326354234919).

Almost surely, 2^{11918699808409} is an apocalyptic number.

11918699808409 is the 3452347-th square number.

11918699808409 is the 1726174-th centered octagonal number.

It is an amenable number.

11918699808409 is a deficient number, since it is larger than the sum of its proper divisors (18488305862).

11918699808409 is an frugal number, since it uses more digits than its factorization.

11918699808409 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10696 (or 5348 counting only the distinct ones).

The product of its (nonzero) digits is 80621568, while the sum is 73.

The spelling of 11918699808409 in words is "eleven trillion, nine hundred eighteen billion, six hundred ninety-nine million, eight hundred eight thousand, four hundred nine".