12565855856521 has 64 divisors (see below), whose sum is σ = 14113345277952. Its totient is φ = 11185278720000.

The previous prime is 12565855856479. The next prime is 12565855856591.

12565855856521 is nontrivially palindromic in base 10.

It is not a de Polignac number, because 12565855856521 - 2²³ = 12565847467913 is a prime.

It is a super-3 number, since 3×12565855856521³ (a number of 40 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12565855856591) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 11560124440 + ... + 11560125526.

It is an arithmetic number, because the mean of its divisors is an integer number (220521019968).

Almost surely, 2^{12565855856521} is an apocalyptic number.

12565855856521 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

12565855856521 is a deficient number, since it is larger than the sum of its proper divisors (1547489421431).

12565855856521 is a wasteful number, since it uses less digits than its factorization.

12565855856521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2095 (or 2073 counting only the distinct ones).

The product of its digits is 144000000, while the sum is 64.

The spelling of 12565855856521 in words is "twelve trillion, five hundred sixty-five billion, eight hundred fifty-five million, eight hundred fifty-six thousand, five hundred twenty-one".