12556265521 has 4 divisors (see below), whose sum is σ = 12558129444. Its totient is φ = 12554401600.

The previous prime is 12556265497. The next prime is 12556265531.

12556265521 is nontrivially palindromic in base 10.

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

It can be written as a sum of positive squares in 2 ways, for example, as 6652033600 + 5904231921 = 81560^2 + 76839^2 .

It is a cyclic number.

It is not a de Polignac number, because 12556265521 - 2¹⁷ = 12556134449 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12556265531) 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, 921820 + ... + 935341.

It is an arithmetic number, because the mean of its divisors is an integer number (3139532361).

Almost surely, 2^12556265521 is an apocalyptic number.

It is an amenable number.

12556265521 is a deficient number, since it is larger than the sum of its proper divisors (1863923).

12556265521 is an equidigital number, since it uses as much as digits as its factorization.

12556265521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1863922.

The product of its digits is 180000, while the sum is 40.

The spelling of 12556265521 in words is "twelve billion, five hundred fifty-six million, two hundred sixty-five thousand, five hundred twenty-one".