18778398894029 has 2 divisors, whose sum is σ = 18778398894030. Its totient is φ = 18778398894028.

The previous prime is 18778398894011. The next prime is 18778398894037. The reversal of 18778398894029 is 92049889387781.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18778398894025 + 4 = 4333405^2 + 2^2 .

It is a cyclic number.

It is not a de Polignac number, because 18778398894029 - 2²⁰ = 18778397845453 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18778398894049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9389199447014 + 9389199447015.

It is an arithmetic number, because the mean of its divisors is an integer number (9389199447015).

Almost surely, 2^{18778398894029} is an apocalyptic number.

It is an amenable number.

18778398894029 is a deficient number, since it is larger than the sum of its proper divisors (1).

18778398894029 is an equidigital number, since it uses as much as digits as its factorization.

18778398894029 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3511517184, while the sum is 83.

The spelling of 18778398894029 in words is "eighteen trillion, seven hundred seventy-eight billion, three hundred ninety-eight million, eight hundred ninety-four thousand, twenty-nine".