12739521 has 4 divisors (see below), whose sum is σ = 16986032. Its totient is φ = 8493012.

The previous prime is 12739513. The next prime is 12739537. The reversal of 12739521 is 12593721.

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 not a de Polignac number, because 12739521 - 2³ = 12739513 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12739121) 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, 2123251 + ... + 2123256.

It is an arithmetic number, because the mean of its divisors is an integer number (4246508).

Almost surely, 2^12739521 is an apocalyptic number.

It is an amenable number.

12739521 is a deficient number, since it is larger than the sum of its proper divisors (4246511).

12739521 is an equidigital number, since it uses as much as digits as its factorization.

12739521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4246510.

The product of its digits is 3780, while the sum is 30.

The square root of 12739521 is about 3569.2465591494. The cubic root of 12739521 is about 233.5524171336.

The spelling of 12739521 in words is "twelve million, seven hundred thirty-nine thousand, five hundred twenty-one".