63989568221 has 2 divisors, whose sum is σ = 63989568222. Its totient is φ = 63989568220.

The previous prime is 63989568173. The next prime is 63989568239. The reversal of 63989568221 is 12286598936.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 61560556996 + 2429011225 = 248114^2 + 49285^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-63989568221 is a prime.

It is a super-2 number, since 2×63989568221² (a number of 22 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (63989568121) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 31994784110 + 31994784111.

It is an arithmetic number, because the mean of its divisors is an integer number (31994784111).

Almost surely, 2^63989568221 is an apocalyptic number.

It is an amenable number.

63989568221 is a deficient number, since it is larger than the sum of its proper divisors (1).

63989568221 is an equidigital number, since it uses as much as digits as its factorization.

63989568221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11197440, while the sum is 59.

The spelling of 63989568221 in words is "sixty-three billion, nine hundred eighty-nine million, five hundred sixty-eight thousand, two hundred twenty-one".