2104021 has 2 divisors, whose sum is σ = 2104022. Its totient is φ = 2104020.

The previous prime is 2104019. The next prime is 2104031. The reversal of 2104021 is 1204012.

It is an a-pointer prime, because the next prime (2104031) can be obtained adding 2104021 to its sum of digits (10).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 2102500 + 1521 = 1450^2 + 39^2 .

It is a cyclic number.

It is not a de Polignac number, because 2104021 - 2¹ = 2104019 is a prime.

Together with 2104019, it forms a pair of twin primes.

It is a Chen prime.

2104021 is a lucky number.

It is a plaindrome in base 13.

It is a junction number, because it is equal to n+sod(n) for n = 2103989 and 2104007.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2104031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1052010 + 1052011.

It is an arithmetic number, because the mean of its divisors is an integer number (1052011).

2^2104021 is an apocalyptic number.

It is an amenable number.

2104021 is a deficient number, since it is larger than the sum of its proper divisors (1).

2104021 is an equidigital number, since it uses as much as digits as its factorization.

2104021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16, while the sum is 10.

The square root of 2104021 is about 1450.5243879370. The cubic root of 2104021 is about 128.1395978608.

Adding to 2104021 its reverse (1204012), we get a palindrome (3308033).

Subtracting from 2104021 its reverse (1204012), we obtain a palindrome (900009).

The spelling of 2104021 in words is "two million, one hundred four thousand, twenty-one".