13811581 has 16 divisors (see below), whose sum is σ = 16374400. Its totient is φ = 11642400.

The previous prime is 13811573. The next prime is 13811587. The reversal of 13811581 is 18511831.

It is not a de Polignac number, because 13811581 - 2³ = 13811573 is a prime.

It is a super-2 number, since 2×13811581² = 381519539439122, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13811587) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 22681 + ... + 23281.

It is an arithmetic number, because the mean of its divisors is an integer number (1023400).

Almost surely, 2^13811581 is an apocalyptic number.

It is an amenable number.

13811581 is a deficient number, since it is larger than the sum of its proper divisors (2562819).

13811581 is an frugal number, since it uses more digits than its factorization.

13811581 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 689 (or 675 counting only the distinct ones).

The product of its digits is 960, while the sum is 28.

The square root of 13811581 is about 3716.3935475135. The cubic root of 13811581 is about 239.9281092547.

The spelling of 13811581 in words is "thirteen million, eight hundred eleven thousand, five hundred eighty-one".