12729991 has 4 divisors (see below), whose sum is σ = 13478832. Its totient is φ = 11981152.

The previous prime is 12729979. The next prime is 12730007. The reversal of 12729991 is 19992721.

It is a happy number.

12729991 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.

It is a cyclic number.

It is not a de Polignac number, because 12729991 - 2⁷ = 12729863 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12729901) 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, 374395 + ... + 374428.

It is an arithmetic number, because the mean of its divisors is an integer number (3369708).

Almost surely, 2^12729991 is an apocalyptic number.

12729991 is a deficient number, since it is larger than the sum of its proper divisors (748841).

12729991 is an equidigital number, since it uses as much as digits as its factorization.

12729991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 748840.

The product of its digits is 20412, while the sum is 40.

The square root of 12729991 is about 3567.9112937404. The cubic root of 12729991 is about 233.4941650803.

The spelling of 12729991 in words is "twelve million, seven hundred twenty-nine thousand, nine hundred ninety-one".