18778057218 has 18 divisors (see below), whose sum is σ = 40687050339. Its totient is φ = 6259158612.

The previous prime is 18778057189. The next prime is 18778057229. The reversal of 18778057218 is 81275087781.

It can be written as a sum of positive squares in only one way, i.e., 9389028609 + 9389028609 = 96897^2 + 96897^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=96897.

It is an unprimeable number.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 565233 + ... + 597531.

Almost surely, 2^18778057218 is an apocalyptic number.

18778057218 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

18778057218 is an abundant number, since it is smaller than the sum of its proper divisors (21908993121).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18778057218 is an frugal number, since it uses more digits than its factorization.

18778057218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64606 (or 32304 counting only the distinct ones).

The product of its (nonzero) digits is 1756160, while the sum is 54.

The spelling of 18778057218 in words is "eighteen billion, seven hundred seventy-eight million, fifty-seven thousand, two hundred eighteen".