2121808 has 30 divisors (see below), whose sum is σ = 4471502. Its totient is φ = 969600.

The previous prime is 2121803. The next prime is 2121809. The reversal of 2121808 is 8081212.

2121808 is digitally balanced in base 5, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 3 ways, for example, as 1056784 + 1065024 = 1028^2 + 1032^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2121803) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 20958 + ... + 21058.

2^2121808 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 2121808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2235751).

2121808 is an abundant number, since it is smaller than the sum of its proper divisors (2349694).

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

2121808 is a wasteful number, since it uses less digits than its factorization.

2121808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223 (or 116 counting only the distinct ones).

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

The square root of 2121808 is about 1456.6427152875. The cubic root of 2121808 is about 128.4996744833.

The spelling of 2121808 in words is "two million, one hundred twenty-one thousand, eight hundred eight".