13688021 has 4 divisors (see below), whose sum is σ = 13695552. Its totient is φ = 13680492.

The previous prime is 13687997. The next prime is 13688027. The reversal of 13688021 is 12088631.

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 a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 13688021 - 2¹⁸ = 13425877 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 (13688027) 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, 836 + ... + 5298.

It is an arithmetic number, because the mean of its divisors is an integer number (3423888).

Almost surely, 2^13688021 is an apocalyptic number.

It is an amenable number.

13688021 is a deficient number, since it is larger than the sum of its proper divisors (7531).

13688021 is an equidigital number, since it uses as much as digits as its factorization.

13688021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7530.

The product of its (nonzero) digits is 2304, while the sum is 29.

The square root of 13688021 is about 3699.7325579020. The cubic root of 13688021 is about 239.2104901478.

The spelling of 13688021 in words is "thirteen million, six hundred eighty-eight thousand, twenty-one".