18687333448921 has 2 divisors, whose sum is σ = 18687333448922. Its totient is φ = 18687333448920.

The previous prime is 18687333448877. The next prime is 18687333448951. The reversal of 18687333448921 is 12984433378681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18031615713225 + 655717735696 = 4246365^2 + 809764^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-18687333448921 is a prime.

It is not a weakly prime, because it can be changed into another prime (18687333448951) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (31) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9343666724460 + 9343666724461.

It is an arithmetic number, because the mean of its divisors is an integer number (9343666724461).

Almost surely, 2^{18687333448921} is an apocalyptic number.

It is an amenable number.

18687333448921 is a deficient number, since it is larger than the sum of its proper divisors (1).

18687333448921 is an equidigital number, since it uses as much as digits as its factorization.

18687333448921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 167215104, while the sum is 67.

The spelling of 18687333448921 in words is "eighteen trillion, six hundred eighty-seven billion, three hundred thirty-three million, four hundred forty-eight thousand, nine hundred twenty-one".