11881809 has 15 divisors (see below), whose sum is σ = 17795833. Its totient is φ = 7900524.

The previous prime is 11881801. The next prime is 11881811. The reversal of 11881809 is 90818811.

The square root of 11881809 is 3447.

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

11881809 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 11881809 - 2³ = 11881801 is a prime.

It is a super-2 number, since 2×11881809² = 282354770224962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (11881801) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 30832 + ... + 31214.

Almost surely, 2^11881809 is an apocalyptic number.

11881809 is the 3447-th square number.

11881809 is the 1724-th centered octagonal number.

It is an amenable number.

11881809 is a deficient number, since it is larger than the sum of its proper divisors (5914024).

11881809 is an frugal number, since it uses more digits than its factorization.

11881809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 778 (or 386 counting only the distinct ones).

The product of its (nonzero) digits is 4608, while the sum is 36.

The cubic root of 11881809 is about 228.1887287767.

Multiplying 11881809 by its sum of digits (36), we get a square (427745124 = 20682²).

The spelling of 11881809 in words is "eleven million, eight hundred eighty-one thousand, eight hundred nine".