12564781601 has 2 divisors, whose sum is σ = 12564781602. Its totient is φ = 12564781600.

The previous prime is 12564781531. The next prime is 12564781637. The reversal of 12564781601 is 10618746521.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8902111201 + 3662670400 = 94351^2 + 60520^2 .

It is an emirp because it is prime and its reverse (10618746521) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 12564781601 - 2²² = 12560587297 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (12564781001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6282390800 + 6282390801.

It is an arithmetic number, because the mean of its divisors is an integer number (6282390801).

Almost surely, 2^12564781601 is an apocalyptic number.

It is an amenable number.

12564781601 is a deficient number, since it is larger than the sum of its proper divisors (1).

12564781601 is an equidigital number, since it uses as much as digits as its factorization.

12564781601 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 80640, while the sum is 41.

The spelling of 12564781601 in words is "twelve billion, five hundred sixty-four million, seven hundred eighty-one thousand, six hundred one".