21221535542063 has 2 divisors, whose sum is σ = 21221535542064. Its totient is φ = 21221535542062.

The previous prime is 21221535541961. The next prime is 21221535542071. The reversal of 21221535542063 is 36024553512212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21221535542063 - 2¹² = 21221535537967 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21221535542063.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21221535542093) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610767771031 + 10610767771032.

It is an arithmetic number, because the mean of its divisors is an integer number (10610767771032).

Almost surely, 2^{21221535542063} is an apocalyptic number.

21221535542063 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221535542063 is an equidigital number, since it uses as much as digits as its factorization.

21221535542063 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432000, while the sum is 41.

The spelling of 21221535542063 in words is "twenty-one trillion, two hundred twenty-one billion, five hundred thirty-five million, five hundred forty-two thousand, sixty-three".