13680521 has 4 divisors (see below), whose sum is σ = 13717572. Its totient is φ = 13643472.

The previous prime is 13680479. The next prime is 13680539. The reversal of 13680521 is 12508631.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12508631 = 19 ⋅658349.

It can be written as a sum of positive squares in 2 ways, for example, as 11155600 + 2524921 = 3340^2 + 1589^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13680521 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (13680221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 17966 + ... + 18711.

It is an arithmetic number, because the mean of its divisors is an integer number (3429393).

Almost surely, 2^13680521 is an apocalyptic number.

It is an amenable number.

13680521 is a deficient number, since it is larger than the sum of its proper divisors (37051).

13680521 is an equidigital number, since it uses as much as digits as its factorization.

13680521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37050.

The product of its (nonzero) digits is 1440, while the sum is 26.

The square root of 13680521 is about 3698.7188322445. The cubic root of 13680521 is about 239.1667924151.

The spelling of 13680521 in words is "thirteen million, six hundred eighty thousand, five hundred twenty-one".