12309581 has 4 divisors (see below), whose sum is σ = 13033692. Its totient is φ = 11585472.

The previous prime is 12309571. The next prime is 12309589. The reversal of 12309581 is 18590321.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18590321 = 269 ⋅69109.

It can be written as a sum of positive squares in 2 ways, for example, as 10530025 + 1779556 = 3245^2 + 1334^2 .

It is a cyclic number.

It is not a de Polignac number, because 12309581 - 2²² = 8115277 is a prime.

It is a super-2 number, since 2×12309581² = 303051568791122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12309589) 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, 362030 + ... + 362063.

It is an arithmetic number, because the mean of its divisors is an integer number (3258423).

Almost surely, 2^12309581 is an apocalyptic number.

It is an amenable number.

12309581 is a deficient number, since it is larger than the sum of its proper divisors (724111).

12309581 is an equidigital number, since it uses as much as digits as its factorization.

12309581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 724110.

The product of its (nonzero) digits is 2160, while the sum is 29.

The square root of 12309581 is about 3508.5012469714. The cubic root of 12309581 is about 230.8949442021.

The spelling of 12309581 in words is "twelve million, three hundred nine thousand, five hundred eighty-one".