13640321 has 2 divisors, whose sum is σ = 13640322. Its totient is φ = 13640320.

The previous prime is 13640299. The next prime is 13640339. The reversal of 13640321 is 12304631.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12567025 + 1073296 = 3545^2 + 1036^2 .

It is an emirp because it is prime and its reverse (12304631) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 13640321 - 2⁶ = 13640257 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 13640293 and 13640302.

It is not a weakly prime, because it can be changed into another prime (13640351) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6820160 + 6820161.

It is an arithmetic number, because the mean of its divisors is an integer number (6820161).

Almost surely, 2^13640321 is an apocalyptic number.

It is an amenable number.

13640321 is a deficient number, since it is larger than the sum of its proper divisors (1).

13640321 is an equidigital number, since it uses as much as digits as its factorization.

13640321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 20.

The square root of 13640321 is about 3693.2805200797. The cubic root of 13640321 is about 238.9322999369.

Adding to 13640321 its reverse (12304631), we get a palindrome (25944952).

The spelling of 13640321 in words is "thirteen million, six hundred forty thousand, three hundred twenty-one".