12721539 has 4 divisors (see below), whose sum is σ = 16962056. Its totient is φ = 8481024.

The previous prime is 12721531. The next prime is 12721549. The reversal of 12721539 is 93512721.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 12721539 - 2³ = 12721531 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12721531) 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, 2120254 + ... + 2120259.

It is an arithmetic number, because the mean of its divisors is an integer number (4240514).

Almost surely, 2^12721539 is an apocalyptic number.

12721539 is a deficient number, since it is larger than the sum of its proper divisors (4240517).

12721539 is an equidigital number, since it uses as much as digits as its factorization.

12721539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4240516.

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

The square root of 12721539 is about 3566.7266505859. The cubic root of 12721539 is about 233.4424779632.

The spelling of 12721539 in words is "twelve million, seven hundred twenty-one thousand, five hundred thirty-nine".