18981844 has 24 divisors (see below), whose sum is σ = 38683008. Its totient is φ = 7980960.

The previous prime is 18981841. The next prime is 18981847. The reversal of 18981844 is 44818981.

It is an interprime number because it is at equal distance from previous prime (18981841) and next prime (18981847).

It is a self number, because there is not a number n which added to its sum of digits gives 18981844.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18981841) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4912 + ... + 7879.

It is an arithmetic number, because the mean of its divisors is an integer number (1611792).

Almost surely, 2^18981844 is an apocalyptic number.

18981844 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

18981844 is an abundant number, since it is smaller than the sum of its proper divisors (19701164).

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

18981844 is a wasteful number, since it uses less digits than its factorization.

18981844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12855 (or 12853 counting only the distinct ones).

The product of its digits is 73728, while the sum is 43.

The square root of 18981844 is about 4356.8158097400. The cubic root of 18981844 is about 266.7551421699.

The spelling of 18981844 in words is "eighteen million, nine hundred eighty-one thousand, eight hundred forty-four".