12991539 has 8 divisors (see below), whose sum is σ = 18896832. Its totient is φ = 7873640.

The previous prime is 12991523. The next prime is 12991541. The reversal of 12991539 is 93519921.

12991539 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 12991539 - 2⁴ = 12991523 is a prime.

It is a zygodrome in base 2.

It is a junction number, because it is equal to n+sod(n) for n = 12991497 and 12991506.

It is not an unprimeable number, because it can be changed into a prime (12991339) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 196809 + ... + 196874.

It is an arithmetic number, because the mean of its divisors is an integer number (2362104).

Almost surely, 2^12991539 is an apocalyptic number.

12991539 is a deficient number, since it is larger than the sum of its proper divisors (5905293).

12991539 is a wasteful number, since it uses less digits than its factorization.

12991539 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 393697.

The product of its digits is 21870, while the sum is 39.

The square root of 12991539 is about 3604.3777548975. The cubic root of 12991539 is about 235.0824457965.

It can be divided in two parts, 12991 and 539, that added together give a triangular number (13530 = T₁₆₄).

The spelling of 12991539 in words is "twelve million, nine hundred ninety-one thousand, five hundred thirty-nine".