13725809921 has 4 divisors (see below), whose sum is σ = 13786276272. Its totient is φ = 13665343572.

The previous prime is 13725809917. The next prime is 13725809927. The reversal of 13725809921 is 12990852731.

It is a happy number.

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: 12990852731 = 29 ⋅447960439.

It is a cyclic number.

It is not a de Polignac number, because 13725809921 - 2² = 13725809917 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13725809927) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 30232835 + ... + 30233288.

It is an arithmetic number, because the mean of its divisors is an integer number (3446569068).

Almost surely, 2^13725809921 is an apocalyptic number.

It is an amenable number.

13725809921 is a deficient number, since it is larger than the sum of its proper divisors (60466351).

13725809921 is an equidigital number, since it uses as much as digits as its factorization.

13725809921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 60466350.

The product of its (nonzero) digits is 272160, while the sum is 47.

The spelling of 13725809921 in words is "thirteen billion, seven hundred twenty-five million, eight hundred nine thousand, nine hundred twenty-one".