2181021 has 16 divisors (see below), whose sum is σ = 3083136. Its totient is φ = 1368576.

The previous prime is 2181017. The next prime is 2181031. The reversal of 2181021 is 1201812.

2181021 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 2181021 - 2² = 2181017 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2181031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4821 + ... + 5253.

It is an arithmetic number, because the mean of its divisors is an integer number (192696).

2^2181021 is an apocalyptic number.

It is an amenable number.

2181021 is a deficient number, since it is larger than the sum of its proper divisors (902115).

2181021 is a wasteful number, since it uses less digits than its factorization.

2181021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 532.

The product of its (nonzero) digits is 32, while the sum is 15.

The square root of 2181021 is about 1476.8280197775. The cubic root of 2181021 is about 129.6840651628.

Adding to 2181021 its reverse (1201812), we get a palindrome (3382833).

The spelling of 2181021 in words is "two million, one hundred eighty-one thousand, twenty-one".