63521644742221 has 2 divisors, whose sum is σ = 63521644742222. Its totient is φ = 63521644742220.

The previous prime is 63521644742201. The next prime is 63521644742249. The reversal of 63521644742221 is 12224744612536.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 60155318832196 + 3366325910025 = 7755986^2 + 1834755^2 .

It is a cyclic number.

It is not a de Polignac number, because 63521644742221 - 2⁷ = 63521644742093 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (63521644742201) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 31760822371110 + 31760822371111.

It is an arithmetic number, because the mean of its divisors is an integer number (31760822371111).

Almost surely, 2^{63521644742221} is an apocalyptic number.

It is an amenable number.

63521644742221 is a deficient number, since it is larger than the sum of its proper divisors (1).

63521644742221 is an equidigital number, since it uses as much as digits as its factorization.

63521644742221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3870720, while the sum is 49.

The spelling of 63521644742221 in words is "sixty-three trillion, five hundred twenty-one billion, six hundred forty-four million, seven hundred forty-two thousand, two hundred twenty-one".