18981000 has 256 divisors, whose sum is σ = 71136000. Its totient is φ = 4665600.

The previous prime is 18980989. The next prime is 18981023. The reversal of 18981000 is 18981.

It is a super-2 number, since 2×18981000² = 720556722000000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 512982 + ... + 513018.

It is an arithmetic number, because the mean of its divisors is an integer number (277875).

Almost surely, 2^18981000 is an apocalyptic number.

18981000 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 18981000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35568000).

18981000 is an abundant number, since it is smaller than the sum of its proper divisors (52155000).

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

18981000 is a wasteful number, since it uses less digits than its factorization.

18981000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86 (or 66 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 27.

The square root of 18981000 is about 4356.7189489339. The cubic root of 18981000 is about 266.7511884852.

Adding to 18981000 its reverse (18981), we get a palindrome (18999981).

18981000 divided by its reverse (18981) gives a cube (1000 = 10³).

The spelling of 18981000 in words is "eighteen million, nine hundred eighty-one thousand".