13665521 has 8 divisors (see below), whose sum is σ = 14108640. Its totient is φ = 13229568.

The previous prime is 13665517. The next prime is 13665523. The reversal of 13665521 is 12556631.

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

It is a cyclic number.

It is not a de Polignac number, because 13665521 - 2² = 13665517 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13665523) 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, 2225 + ... + 5681.

It is an arithmetic number, because the mean of its divisors is an integer number (1763580).

Almost surely, 2^13665521 is an apocalyptic number.

It is an amenable number.

13665521 is a deficient number, since it is larger than the sum of its proper divisors (443119).

13665521 is an equidigital number, since it uses as much as digits as its factorization.

13665521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3583.

The product of its digits is 5400, while the sum is 29.

The square root of 13665521 is about 3696.6905469622. The cubic root of 13665521 is about 239.0793490140.

The spelling of 13665521 in words is "thirteen million, six hundred sixty-five thousand, five hundred twenty-one".