13665261 has 4 divisors (see below), whose sum is σ = 18220352. Its totient is φ = 9110172.

The previous prime is 13665257. The next prime is 13665269. The reversal of 13665261 is 16256631.

13665261 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16256631 = 3 ⋅5418877.

It is not a de Polignac number, because 13665261 - 2² = 13665257 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 (13665269) 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, 2277541 + ... + 2277546.

It is an arithmetic number, because the mean of its divisors is an integer number (4555088).

Almost surely, 2^13665261 is an apocalyptic number.

It is an amenable number.

13665261 is a deficient number, since it is larger than the sum of its proper divisors (4555091).

13665261 is an equidigital number, since it uses as much as digits as its factorization.

13665261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4555090.

The product of its digits is 6480, while the sum is 30.

The square root of 13665261 is about 3696.6553802052. The cubic root of 13665261 is about 239.0778327643.

The spelling of 13665261 in words is "thirteen million, six hundred sixty-five thousand, two hundred sixty-one".