18081000 has 288 divisors, whose sum is σ = 72825480. Its totient is φ = 4032000.

The previous prime is 18080999. The next prime is 18081023. The reversal of 18081000 is 18081.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1483524 + 16597476 = 1218^2 + 4074^2 .

It is a super-2 number, since 2×18081000² = 653845122000000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 440980 + ... + 441020.

Almost surely, 2^18081000 is an apocalyptic number.

18081000 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 18081000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36412740).

18081000 is an abundant number, since it is smaller than the sum of its proper divisors (54744480).

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

18081000 is a wasteful number, since it uses less digits than its factorization.

18081000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 82 (or 58 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 18.

The square root of 18081000 is about 4252.1759135765. The cubic root of 18081000 is about 262.4666624330.

Adding to 18081000 its reverse (18081), we get a palindrome (18099081).

18081000 divided by its reverse (18081) gives a cube (1000 = 10³).

The spelling of 18081000 in words is "eighteen million, eighty-one thousand".