12642921607681 has 4 divisors (see below), whose sum is σ = 12643688931412. Its totient is φ = 12642154283952.

The previous prime is 12642921607651. The next prime is 12642921607727. The reversal of 12642921607681 is 18670612924621.

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 6009283515456 + 6633638092225 = 2451384^2 + 2575585^2 .

It is a cyclic number.

It is not a de Polignac number, because 12642921607681 - 2¹⁷ = 12642921476609 is a prime.

It is a super-2 number, since 2×12642921607681² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12642921607601) 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, 383637150 + ... + 383670103.

It is an arithmetic number, because the mean of its divisors is an integer number (3160922232853).

Almost surely, 2^{12642921607681} is an apocalyptic number.

It is an amenable number.

12642921607681 is a deficient number, since it is larger than the sum of its proper divisors (767323731).

12642921607681 is an equidigital number, since it uses as much as digits as its factorization.

12642921607681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 767323730.

The product of its (nonzero) digits is 3483648, while the sum is 55.

The spelling of 12642921607681 in words is "twelve trillion, six hundred forty-two billion, nine hundred twenty-one million, six hundred seven thousand, six hundred eighty-one".