1998180 has 72 divisors (see below), whose sum is σ = 6427512. Its totient is φ = 500736.

The previous prime is 1998169. The next prime is 1998181. The reversal of 1998180 is 818991.

It can be written as a sum of positive squares in 4 ways, for example, as 207936 + 1790244 = 456^2 + 1338^2 .

It is a Harshad number since it is a multiple of its sum of digits (36).

It is not an unprimeable number, because it can be changed into a prime (1998181) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 2734 + ... + 3386.

It is an arithmetic number, because the mean of its divisors is an integer number (89271).

2^1998180 is an apocalyptic number.

1998180 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 1998180, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3213756).

1998180 is an abundant number, since it is smaller than the sum of its proper divisors (4429332).

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

1998180 is a wasteful number, since it uses less digits than its factorization.

1998180 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 685 (or 680 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 36.

The square root of 1998180 is about 1413.5699487468. The cubic root of 1998180 is about 125.9538757858.

The spelling of 1998180 in words is "one million, nine hundred ninety-eight thousand, one hundred eighty".