18778398894026 has 4 divisors (see below), whose sum is σ = 28167598341042. Its totient is φ = 9389199447012.

The previous prime is 18778398894011. The next prime is 18778398894029. The reversal of 18778398894026 is 62049889387781.

It is a Cunningham number, because it is equal to 4333405²+1.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 18778398894025 + 1 = 4333405^2 + 1^2 .

It is not an unprimeable number, because it can be changed into a prime (18778398894029) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4694599723505 + ... + 4694599723508.

Almost surely, 2^{18778398894026} is an apocalyptic number.

18778398894026 is a deficient number, since it is larger than the sum of its proper divisors (9389199447016).

18778398894026 is an equidigital number, since it uses as much as digits as its factorization.

18778398894026 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9389199447015.

The product of its (nonzero) digits is 2341011456, while the sum is 80.

The spelling of 18778398894026 in words is "eighteen trillion, seven hundred seventy-eight billion, three hundred ninety-eight million, eight hundred ninety-four thousand, twenty-six".