13665613 has 8 divisors (see below), whose sum is σ = 14826168. Its totient is φ = 12520704.

The previous prime is 13665607. The next prime is 13665623. The reversal of 13665613 is 31656631.

It can be written as a sum of positive squares in 4 ways, for example, as 1261129 + 12404484 = 1123^2 + 3522^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 13665613 - 2⁹ = 13665101 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13665623) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2056 + ... + 5617.

It is an arithmetic number, because the mean of its divisors is an integer number (1853271).

Almost surely, 2^13665613 is an apocalyptic number.

13665613 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

It is an amenable number.

13665613 is a deficient number, since it is larger than the sum of its proper divisors (1160555).

13665613 is a wasteful number, since it uses less digits than its factorization.

13665613 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7823.

The product of its digits is 9720, while the sum is 31.

The square root of 13665613 is about 3696.7029905038. The cubic root of 13665613 is about 239.0798855285.

The spelling of 13665613 in words is "thirteen million, six hundred sixty-five thousand, six hundred thirteen".