13678781221 has 4 divisors (see below), whose sum is σ = 15632892832. Its totient is φ = 11724669612.

The previous prime is 13678781197. The next prime is 13678781227. The reversal of 13678781221 is 12218787631.

13678781221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13678781221 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 (13678781227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 977055795 + ... + 977055808.

It is an arithmetic number, because the mean of its divisors is an integer number (3908223208).

Almost surely, 2^13678781221 is an apocalyptic number.

It is an amenable number.

13678781221 is a deficient number, since it is larger than the sum of its proper divisors (1954111611).

13678781221 is an equidigital number, since it uses as much as digits as its factorization.

13678781221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1954111610.

The product of its digits is 225792, while the sum is 46.

The spelling of 13678781221 in words is "thirteen billion, six hundred seventy-eight million, seven hundred eighty-one thousand, two hundred twenty-one".