56660221 has 2 divisors, whose sum is σ = 56660222. Its totient is φ = 56660220.

The previous prime is 56660189. The next prime is 56660243. The reversal of 56660221 is 12206665.

56660221 is digitally balanced in base 2, 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., 56625625 + 34596 = 7525^2 + 186^2 .

It is a cyclic number.

It is not a de Polignac number, because 56660221 - 2⁵ = 56660189 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 56660221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (56660291) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 28330110 + 28330111.

It is an arithmetic number, because the mean of its divisors is an integer number (28330111).

Almost surely, 2^56660221 is an apocalyptic number.

It is an amenable number.

56660221 is a deficient number, since it is larger than the sum of its proper divisors (1).

56660221 is an equidigital number, since it uses as much as digits as its factorization.

56660221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4320, while the sum is 28.

The square root of 56660221 is about 7527.2983865395. The cubic root of 56660221 is about 384.0838869285.

Adding to 56660221 its reverse (12206665), we get a palindrome (68866886).

The spelling of 56660221 in words is "fifty-six million, six hundred sixty thousand, two hundred twenty-one".