18671861993 has 2 divisors, whose sum is σ = 18671861994. Its totient is φ = 18671861992.

The previous prime is 18671861953. The next prime is 18671862023. The reversal of 18671861993 is 39916817681.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 15565806169 + 3106055824 = 124763^2 + 55732^2 .

It is a cyclic number.

It is not a de Polignac number, because 18671861993 - 2¹⁰ = 18671860969 is a prime.

It is not a weakly prime, because it can be changed into another prime (18671861953) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9335930996 + 9335930997.

It is an arithmetic number, because the mean of its divisors is an integer number (9335930997).

Almost surely, 2^18671861993 is an apocalyptic number.

It is an amenable number.

18671861993 is a deficient number, since it is larger than the sum of its proper divisors (1).

18671861993 is an equidigital number, since it uses as much as digits as its factorization.

18671861993 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3919104, while the sum is 59.

The spelling of 18671861993 in words is "eighteen billion, six hundred seventy-one million, eight hundred sixty-one thousand, nine hundred ninety-three".