12561421651 has 2 divisors, whose sum is σ = 12561421652. Its totient is φ = 12561421650.

The previous prime is 12561421643. The next prime is 12561421657. The reversal of 12561421651 is 15612416521.

12561421651 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 12561421651 - 2³ = 12561421643 is a prime.

It is not a weakly prime, because it can be changed into another prime (12561421657) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6280710825 + 6280710826.

It is an arithmetic number, because the mean of its divisors is an integer number (6280710826).

Almost surely, 2^12561421651 is an apocalyptic number.

12561421651 is a deficient number, since it is larger than the sum of its proper divisors (1).

12561421651 is an equidigital number, since it uses as much as digits as its factorization.

12561421651 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 14400, while the sum is 34.

The spelling of 12561421651 in words is "twelve billion, five hundred sixty-one million, four hundred twenty-one thousand, six hundred fifty-one".