57821821 has 2 divisors, whose sum is σ = 57821822. Its totient is φ = 57821820.

The previous prime is 57821801. The next prime is 57821843. The reversal of 57821821 is 12812875.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 48149721 + 9672100 = 6939^2 + 3110^2 .

It is a cyclic number.

It is not a de Polignac number, because 57821821 - 2²³ = 49433213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (57821801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28910910 + 28910911.

It is an arithmetic number, because the mean of its divisors is an integer number (28910911).

Almost surely, 2^57821821 is an apocalyptic number.

It is an amenable number.

57821821 is a deficient number, since it is larger than the sum of its proper divisors (1).

57821821 is an equidigital number, since it uses as much as digits as its factorization.

57821821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8960, while the sum is 34.

The square root of 57821821 is about 7604.0660833530. The cubic root of 57821821 is about 386.6908730222.

The spelling of 57821821 in words is "fifty-seven million, eight hundred twenty-one thousand, eight hundred twenty-one".