12421620041561 has 4 divisors (see below), whose sum is σ = 12421629934032. Its totient is φ = 12421610149092.

The previous prime is 12421620041503. The next prime is 12421620041647. The reversal of 12421620041561 is 16514002612421.

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, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12421620041561 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (12421620041261) 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, 2732471 + ... + 5684156.

It is an arithmetic number, because the mean of its divisors is an integer number (3105407483508).

Almost surely, 2^{12421620041561} is an apocalyptic number.

It is an amenable number.

12421620041561 is a deficient number, since it is larger than the sum of its proper divisors (9892471).

12421620041561 is an equidigital number, since it uses as much as digits as its factorization.

12421620041561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9892470.

The product of its (nonzero) digits is 23040, while the sum is 35.

Adding to 12421620041561 its reverse (16514002612421), we get a palindrome (28935622653982).

The spelling of 12421620041561 in words is "twelve trillion, four hundred twenty-one billion, six hundred twenty million, forty-one thousand, five hundred sixty-one".