12451643921 has 2 divisors, whose sum is σ = 12451643922. Its totient is φ = 12451643920.

The previous prime is 12451643917. The next prime is 12451643933. The reversal of 12451643921 is 12934615421.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 11484122896 + 967521025 = 107164^2 + 31105^2 .

It is a cyclic number.

It is not a de Polignac number, because 12451643921 - 2² = 12451643917 is a prime.

It is not a weakly prime, because it can be changed into another prime (12451643621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6225821960 + 6225821961.

It is an arithmetic number, because the mean of its divisors is an integer number (6225821961).

Almost surely, 2^12451643921 is an apocalyptic number.

It is an amenable number.

12451643921 is a deficient number, since it is larger than the sum of its proper divisors (1).

12451643921 is an equidigital number, since it uses as much as digits as its factorization.

12451643921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51840, while the sum is 38.

The spelling of 12451643921 in words is "twelve billion, four hundred fifty-one million, six hundred forty-three thousand, nine hundred twenty-one".