13666591 has 4 divisors (see below), whose sum is σ = 13673992. Its totient is φ = 13659192.

The previous prime is 13666553. The next prime is 13666603. The reversal of 13666591 is 19566631.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 13666591 - 2⁷ = 13666463 is a prime.

It is a super-2 number, since 2×13666591² = 373551419122562, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 13666591.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13666091) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1621 + ... + 5473.

It is an arithmetic number, because the mean of its divisors is an integer number (3418498).

Almost surely, 2^13666591 is an apocalyptic number.

13666591 is a deficient number, since it is larger than the sum of its proper divisors (7401).

13666591 is an equidigital number, since it uses as much as digits as its factorization.

13666591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7400.

The product of its digits is 29160, while the sum is 37.

The square root of 13666591 is about 3696.8352681720. The cubic root of 13666591 is about 239.0855887621.

The spelling of 13666591 in words is "thirteen million, six hundred sixty-six thousand, five hundred ninety-one".