2104204021 has 2 divisors, whose sum is σ = 2104204022. Its totient is φ = 2104204020.

The previous prime is 2104204007. The next prime is 2104204027. The reversal of 2104204021 is 1204024012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1712718225 + 391485796 = 41385^2 + 19786^2 .

It is a cyclic number.

It is not a de Polignac number, because 2104204021 - 2⁵ = 2104203989 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 2104203986 and 2104204004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2104204027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1052102010 + 1052102011.

It is an arithmetic number, because the mean of its divisors is an integer number (1052102011).

Almost surely, 2^2104204021 is an apocalyptic number.

It is an amenable number.

2104204021 is a deficient number, since it is larger than the sum of its proper divisors (1).

2104204021 is an equidigital number, since it uses as much as digits as its factorization.

2104204021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 128, while the sum is 16.

The square root of 2104204021 is about 45871.6036453926. The cubic root of 2104204021 is about 1281.4331321623.

Adding to 2104204021 its reverse (1204024012), we get a palindrome (3308228033).

Subtracting from 2104204021 its reverse (1204024012), we obtain a square (900180009 = 30003²).

The spelling of 2104204021 in words is "two billion, one hundred four million, two hundred four thousand, twenty-one".