18117881980 has 24 divisors (see below), whose sum is σ = 41506421040. Its totient is φ = 6588320640.

The previous prime is 18117881939. The next prime is 18117881981. The reversal of 18117881980 is 8918871181.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18117881981) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41176785 + ... + 41177224.

It is an arithmetic number, because the mean of its divisors is an integer number (1729434210).

Almost surely, 2^18117881980 is an apocalyptic number.

18117881980 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

18117881980 is an abundant number, since it is smaller than the sum of its proper divisors (23388539060).

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

18117881980 is a wasteful number, since it uses less digits than its factorization.

18117881980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82354029 (or 82354027 counting only the distinct ones).

The product of its (nonzero) digits is 258048, while the sum is 52.

The spelling of 18117881980 in words is "eighteen billion, one hundred seventeen million, eight hundred eighty-one thousand, nine hundred eighty".