13665321 has 16 divisors (see below), whose sum is σ = 20793600. Its totient is φ = 8863344.

The previous prime is 13665317. The next prime is 13665343. The reversal of 13665321 is 12356631.

13665321 is a `hidden beast` number, since 1 + 3 + 6 + 653 + 2 + 1 = 666.

It is not a de Polignac number, because 13665321 - 2² = 13665317 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13665371) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 5841 + ... + 7838.

It is an arithmetic number, because the mean of its divisors is an integer number (1299600).

Almost surely, 2^13665321 is an apocalyptic number.

It is an amenable number.

13665321 is a deficient number, since it is larger than the sum of its proper divisors (7128279).

13665321 is a wasteful number, since it uses less digits than its factorization.

13665321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13725 (or 13719 counting only the distinct ones).

The product of its digits is 3240, while the sum is 27.

The square root of 13665321 is about 3696.6634956404. The cubic root of 13665321 is about 239.0781826698.

The spelling of 13665321 in words is "thirteen million, six hundred sixty-five thousand, three hundred twenty-one".