63566821 has 2 divisors, whose sum is σ = 63566822. Its totient is φ = 63566820.

The previous prime is 63566809. The next prime is 63566843. The reversal of 63566821 is 12866536.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 49773025 + 13793796 = 7055^2 + 3714^2 .

It is a cyclic number.

It is not a de Polignac number, because 63566821 - 2¹¹ = 63564773 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (63566801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 31783410 + 31783411.

It is an arithmetic number, because the mean of its divisors is an integer number (31783411).

Almost surely, 2^63566821 is an apocalyptic number.

It is an amenable number.

63566821 is a deficient number, since it is larger than the sum of its proper divisors (1).

63566821 is an equidigital number, since it uses as much as digits as its factorization.

63566821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51840, while the sum is 37.

The square root of 63566821 is about 7972.8803452705. The cubic root of 63566821 is about 399.0954999910.

The spelling of 63566821 in words is "sixty-three million, five hundred sixty-six thousand, eight hundred twenty-one".