18781980 has 96 divisors (see below), whose sum is σ = 60673536. Its totient is φ = 4252416.

The previous prime is 18781979. The next prime is 18781993. The reversal of 18781980 is 8918781.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 82627 + ... + 82853.

It is an arithmetic number, because the mean of its divisors is an integer number (632016).

Almost surely, 2^18781980 is an apocalyptic number.

18781980 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18781980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30336768).

18781980 is an abundant number, since it is smaller than the sum of its proper divisors (41891556).

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

18781980 is a wasteful number, since it uses less digits than its factorization.

18781980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 443 (or 441 counting only the distinct ones).

The product of its (nonzero) digits is 32256, while the sum is 42.

The square root of 18781980 is about 4333.8181780042. The cubic root of 18781980 is about 265.8155957107.

The spelling of 18781980 in words is "eighteen million, seven hundred eighty-one thousand, nine hundred eighty".