3804521207821 has 2 divisors, whose sum is σ = 3804521207822. Its totient is φ = 3804521207820.

The previous prime is 3804521207803. The next prime is 3804521207863. The reversal of 3804521207821 is 1287021254083.

3804521207821 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 3712612190596 + 91909017225 = 1926814^2 + 303165^2 .

It is a cyclic number.

It is not a de Polignac number, because 3804521207821 - 2⁹ = 3804521207309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (3804521207521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1902260603910 + 1902260603911.

It is an arithmetic number, because the mean of its divisors is an integer number (1902260603911).

Almost surely, 2^{3804521207821} is an apocalyptic number.

It is an amenable number.

3804521207821 is a deficient number, since it is larger than the sum of its proper divisors (1).

3804521207821 is an equidigital number, since it uses as much as digits as its factorization.

3804521207821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 215040, while the sum is 43.

The spelling of 3804521207821 in words is "three trillion, eight hundred four billion, five hundred twenty-one million, two hundred seven thousand, eight hundred twenty-one".