2103821 has 2 divisors, whose sum is σ = 2103822. Its totient is φ = 2103820.

The previous prime is 2103817. The next prime is 2103839. The reversal of 2103821 is 1283012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1406596 + 697225 = 1186^2 + 835^2 .

It is a cyclic number.

It is not a de Polignac number, because 2103821 - 2² = 2103817 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2103821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2103811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1051910 + 1051911.

It is an arithmetic number, because the mean of its divisors is an integer number (1051911).

2^2103821 is an apocalyptic number.

It is an amenable number.

2103821 is a deficient number, since it is larger than the sum of its proper divisors (1).

2103821 is an equidigital number, since it uses as much as digits as its factorization.

2103821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 96, while the sum is 17.

The square root of 2103821 is about 1450.4554457135. The cubic root of 2103821 is about 128.1355375827.

Adding to 2103821 its reverse (1283012), we get a palindrome (3386833).

It can be divided in two parts, 2 and 103821, that added together give a cube (103823 = 47³).

The spelling of 2103821 in words is "two million, one hundred three thousand, eight hundred twenty-one".