57809821 has 2 divisors, whose sum is σ = 57809822. Its totient is φ = 57809820.

The previous prime is 57809813. The next prime is 57809887. The reversal of 57809821 is 12890875.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 42902500 + 14907321 = 6550^2 + 3861^2 .

It is a cyclic number.

It is not a de Polignac number, because 57809821 - 2³ = 57809813 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (57809891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28904910 + 28904911.

It is an arithmetic number, because the mean of its divisors is an integer number (28904911).

Almost surely, 2^57809821 is an apocalyptic number.

It is an amenable number.

57809821 is a deficient number, since it is larger than the sum of its proper divisors (1).

57809821 is an equidigital number, since it uses as much as digits as its factorization.

57809821 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 40320, while the sum is 40.

The square root of 57809821 is about 7603.2769908770. The cubic root of 57809821 is about 386.6641206564.

The spelling of 57809821 in words is "fifty-seven million, eight hundred nine thousand, eight hundred twenty-one".