57660221 has 2 divisors, whose sum is σ = 57660222. Its totient is φ = 57660220.

The previous prime is 57660199. The next prime is 57660223. The reversal of 57660221 is 12206675.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57002500 + 657721 = 7550^2 + 811^2 .

It is a cyclic number.

It is not a de Polignac number, because 57660221 - 2⁶ = 57660157 is a prime.

Together with 57660223, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (57660223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28830110 + 28830111.

It is an arithmetic number, because the mean of its divisors is an integer number (28830111).

Almost surely, 2^57660221 is an apocalyptic number.

It is an amenable number.

57660221 is a deficient number, since it is larger than the sum of its proper divisors (1).

57660221 is an equidigital number, since it uses as much as digits as its factorization.

57660221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5040, while the sum is 29.

The square root of 57660221 is about 7593.4327546901. The cubic root of 57660221 is about 386.3302966320.

Adding to 57660221 its reverse (12206675), we get a palindrome (69866896).

The spelling of 57660221 in words is "fifty-seven million, six hundred sixty thousand, two hundred twenty-one".