13581809 has 4 divisors (see below), whose sum is σ = 13702116. Its totient is φ = 13461504.

The previous prime is 13581781. The next prime is 13581811. The reversal of 13581809 is 90818531.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90818531 = 311 ⋅292021.

It can be written as a sum of positive squares in 2 ways, for example, as 908209 + 12673600 = 953^2 + 3560^2 .

It is a cyclic number.

It is not a de Polignac number, because 13581809 - 2¹⁶ = 13516273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13581839) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 59984 + ... + 60209.

It is an arithmetic number, because the mean of its divisors is an integer number (3425529).

Almost surely, 2^13581809 is an apocalyptic number.

It is an amenable number.

13581809 is a deficient number, since it is larger than the sum of its proper divisors (120307).

13581809 is a wasteful number, since it uses less digits than its factorization.

13581809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120306.

The product of its (nonzero) digits is 8640, while the sum is 35.

The square root of 13581809 is about 3685.3505939056. The cubic root of 13581809 is about 238.5901661315.

The spelling of 13581809 in words is "thirteen million, five hundred eighty-one thousand, eight hundred nine".