12621845809421 has 4 divisors (see below), whose sum is σ = 12702239731932. Its totient is φ = 12541451886912.

The previous prime is 12621845809393. The next prime is 12621845809427. The reversal of 12621845809421 is 12490854812621.

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 2295012904900 + 10326832904521 = 1514930^2 + 3213539^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12621845809421 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (12621845809427) 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, 40196961020 + ... + 40196961333.

It is an arithmetic number, because the mean of its divisors is an integer number (3175559932983).

Almost surely, 2^{12621845809421} is an apocalyptic number.

It is an amenable number.

12621845809421 is a deficient number, since it is larger than the sum of its proper divisors (80393922511).

12621845809421 is an equidigital number, since it uses as much as digits as its factorization.

12621845809421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80393922510.

The product of its (nonzero) digits is 2211840, while the sum is 53.

The spelling of 12621845809421 in words is "twelve trillion, six hundred twenty-one billion, eight hundred forty-five million, eight hundred nine thousand, four hundred twenty-one".