2181000 has 64 divisors (see below), whose sum is σ = 6814080. Its totient is φ = 580800.

The previous prime is 2180999. The next prime is 2181007. The reversal of 2181000 is 1812.

It is a happy number.

It is a super-2 number, since 2×2181000² = 9513522000000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is not an unprimeable number, because it can be changed into a prime (2181007) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2637 + ... + 3363.

It is an arithmetic number, because the mean of its divisors is an integer number (106470).

2^2181000 is an apocalyptic number.

2181000 is a gapful number since it is divisible by the number (20) 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 2181000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3407040).

2181000 is an abundant number, since it is smaller than the sum of its proper divisors (4633080).

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

2181000 is a wasteful number, since it uses less digits than its factorization.

2181000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 751 (or 737 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

The square root of 2181000 is about 1476.8209099278. The cubic root of 2181000 is about 129.6836489397.

Adding to 2181000 its reverse (1812), we get a palindrome (2182812).

The spelling of 2181000 in words is "two million, one hundred eighty-one thousand".