4855721821 has 2 divisors, whose sum is σ = 4855721822. Its totient is φ = 4855721820.

The previous prime is 4855721791. The next prime is 4855721831. The reversal of 4855721821 is 1281275584.

4855721821 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4845552100 + 10169721 = 69610^2 + 3189^2 .

It is a cyclic number.

It is not a de Polignac number, because 4855721821 - 2⁹ = 4855721309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4855721831) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2427860910 + 2427860911.

It is an arithmetic number, because the mean of its divisors is an integer number (2427860911).

Almost surely, 2^4855721821 is an apocalyptic number.

It is an amenable number.

4855721821 is a deficient number, since it is larger than the sum of its proper divisors (1).

4855721821 is an equidigital number, since it uses as much as digits as its factorization.

4855721821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 179200, while the sum is 43.

The square root of 4855721821 is about 69683.0095575672. The cubic root of 4855721821 is about 1693.3676788411.

The spelling of 4855721821 in words is "four billion, eight hundred fifty-five million, seven hundred twenty-one thousand, eight hundred twenty-one".