13645974821 has 4 divisors (see below), whose sum is σ = 13678543200. Its totient is φ = 13613406444.

The previous prime is 13645974799. The next prime is 13645974827. The reversal of 13645974821 is 12847954631.

It is a happy number.

13645974821 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, and also an emirpimes, since its reverse is a distinct semiprime: 12847954631 = 37897 ⋅339023.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-13645974821 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 13645974821.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13645974827) 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, 16283561 + ... + 16284398.

It is an arithmetic number, because the mean of its divisors is an integer number (3419635800).

Almost surely, 2^13645974821 is an apocalyptic number.

It is an amenable number.

13645974821 is a deficient number, since it is larger than the sum of its proper divisors (32568379).

13645974821 is an equidigital number, since it uses as much as digits as its factorization.

13645974821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32568378.

The product of its digits is 1451520, while the sum is 50.

The spelling of 13645974821 in words is "thirteen billion, six hundred forty-five million, nine hundred seventy-four thousand, eight hundred twenty-one".