12561221503 has 2 divisors, whose sum is σ = 12561221504. Its totient is φ = 12561221502.

The previous prime is 12561221489. The next prime is 12561221549. The reversal of 12561221503 is 30512216521.

It is a weak prime.

It is an emirp because it is prime and its reverse (30512216521) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12561221503 - 2¹³ = 12561213311 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12561222503) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6280610751 + 6280610752.

It is an arithmetic number, because the mean of its divisors is an integer number (6280610752).

Almost surely, 2^12561221503 is an apocalyptic number.

12561221503 is a deficient number, since it is larger than the sum of its proper divisors (1).

12561221503 is an equidigital number, since it uses as much as digits as its factorization.

12561221503 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3600, while the sum is 28.

The spelling of 12561221503 in words is "twelve billion, five hundred sixty-one million, two hundred twenty-one thousand, five hundred three".