2181312 has 84 divisors (see below), whose sum is σ = 7158736. Its totient is φ = 622080.

The previous prime is 2181271. The next prime is 2181329. The reversal of 2181312 is 2131812.

It is a tau number, because it is divible by the number of its divisors (84).

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

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is an Ulam number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 3762 + ... + 4302.

2^2181312 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 2181312, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3579368).

2181312 is an abundant number, since it is smaller than the sum of its proper divisors (4977424).

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

2181312 is a wasteful number, since it uses less digits than its factorization.

2181312 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 566 (or 553 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

The square root of 2181312 is about 1476.9265384575. The cubic root of 2181312 is about 129.6898325511.

2181312 divided by its product of digits (96) gives a palindrome (22722).

The spelling of 2181312 in words is "two million, one hundred eighty-one thousand, three hundred twelve".