18021280 has 48 divisors (see below), whose sum is σ = 42898464. Its totient is φ = 7153920.

The previous prime is 18021271. The next prime is 18021281. The reversal of 18021280 is 8212081.

It is not an unprimeable number, because it can be changed into a prime (18021281) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 25735 + ... + 26425.

It is an arithmetic number, because the mean of its divisors is an integer number (893718).

Almost surely, 2^18021280 is an apocalyptic number.

18021280 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 18021280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21449232).

18021280 is an abundant number, since it is smaller than the sum of its proper divisors (24877184).

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

18021280 is a wasteful number, since it uses less digits than its factorization.

18021280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 869 (or 861 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 22.

The square root of 18021280 is about 4245.1478183922. The cubic root of 18021280 is about 262.1773753728.

The spelling of 18021280 in words is "eighteen million, twenty-one thousand, two hundred eighty".