1218815999873 has 2 divisors, whose sum is σ = 1218815999874. Its totient is φ = 1218815999872.

The previous prime is 1218815999857. The next prime is 1218816000011. The reversal of 1218815999873 is 3789995188121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1217264270209 + 1551729664 = 1103297^2 + 39392^2 .

It is an emirp because it is prime and its reverse (3789995188121) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1218815999873 - 2⁴ = 1218815999857 is a prime.

It is a super-2 number, since 2×1218815999873² (a number of 25 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1218815999797 and 1218815999806.

It is not a weakly prime, because it can be changed into another prime (1218815999813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 609407999936 + 609407999937.

It is an arithmetic number, because the mean of its divisors is an integer number (609407999937).

Almost surely, 2^{1218815999873} is an apocalyptic number.

It is an amenable number.

1218815999873 is a deficient number, since it is larger than the sum of its proper divisors (1).

1218815999873 is an equidigital number, since it uses as much as digits as its factorization.

1218815999873 is an evil number, because the sum of its binary digits is even.

The product of its digits is 78382080, while the sum is 71.

The spelling of 1218815999873 in words is "one trillion, two hundred eighteen billion, eight hundred fifteen million, nine hundred ninety-nine thousand, eight hundred seventy-three".