12018778509821 has 2 divisors, whose sum is σ = 12018778509822. Its totient is φ = 12018778509820.

The previous prime is 12018778509767. The next prime is 12018778509841. The reversal of 12018778509821 is 12890587781021.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 12018778509721 + 100 = 3466811^2 + 10^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-12018778509821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (12018778509841) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 6009389254910 + 6009389254911.

It is an arithmetic number, because the mean of its divisors is an integer number (6009389254911).

Almost surely, 2^{12018778509821} is an apocalyptic number.

It is an amenable number.

12018778509821 is a deficient number, since it is larger than the sum of its proper divisors (1).

12018778509821 is an equidigital number, since it uses as much as digits as its factorization.

12018778509821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4515840, while the sum is 59.

The spelling of 12018778509821 in words is "twelve trillion, eighteen billion, seven hundred seventy-eight million, five hundred nine thousand, eight hundred twenty-one".