12871721 has 4 divisors (see below), whose sum is σ = 13549200. Its totient is φ = 12194244.

The previous prime is 12871709. The next prime is 12871741. The reversal of 12871721 is 12717821.

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: 12717821 = 19 ⋅669359.

It is a cyclic number.

It is not a de Polignac number, because 12871721 - 2⁶ = 12871657 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12871741) 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, 338711 + ... + 338748.

It is an arithmetic number, because the mean of its divisors is an integer number (3387300).

Almost surely, 2^12871721 is an apocalyptic number.

It is an amenable number.

12871721 is a deficient number, since it is larger than the sum of its proper divisors (677479).

12871721 is an equidigital number, since it uses as much as digits as its factorization.

12871721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 677478.

The product of its digits is 1568, while the sum is 29.

The square root of 12871721 is about 3587.7180769955. The cubic root of 12871721 is about 234.3575086443.

The spelling of 12871721 in words is "twelve million, eight hundred seventy-one thousand, seven hundred twenty-one".