21663551420033 has 2 divisors, whose sum is σ = 21663551420034. Its totient is φ = 21663551420032.

The previous prime is 21663551420011. The next prime is 21663551420059. The reversal of 21663551420033 is 33002415536612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14228942104129 + 7434609315904 = 3772127^2 + 2726648^2 .

It is a cyclic number.

It is not a de Polignac number, because 21663551420033 - 2²⁴ = 21663534642817 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21663551420933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10831775710016 + 10831775710017.

It is an arithmetic number, because the mean of its divisors is an integer number (10831775710017).

Almost surely, 2^{21663551420033} is an apocalyptic number.

It is an amenable number.

21663551420033 is a deficient number, since it is larger than the sum of its proper divisors (1).

21663551420033 is an equidigital number, since it uses as much as digits as its factorization.

21663551420033 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 388800, while the sum is 41.

Adding to 21663551420033 its reverse (33002415536612), we get a palindrome (54665966956645).

The spelling of 21663551420033 in words is "twenty-one trillion, six hundred sixty-three billion, five hundred fifty-one million, four hundred twenty thousand, thirty-three".