12643858581 has 4 divisors (see below), whose sum is σ = 16858478112. Its totient is φ = 8429239052.

The previous prime is 12643858571. The next prime is 12643858607. The reversal of 12643858581 is 18585834621.

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 a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12643858581 is a prime.

It is a super-2 number, since 2×12643858581² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12643858571) 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, 2107309761 + ... + 2107309766.

It is an arithmetic number, because the mean of its divisors is an integer number (4214619528).

Almost surely, 2^12643858581 is an apocalyptic number.

It is an amenable number.

12643858581 is a deficient number, since it is larger than the sum of its proper divisors (4214619531).

12643858581 is an equidigital number, since it uses as much as digits as its factorization.

12643858581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4214619530.

The product of its digits is 1843200, while the sum is 51.

The spelling of 12643858581 in words is "twelve billion, six hundred forty-three million, eight hundred fifty-eight thousand, five hundred eighty-one".