21010533402517 has 2 divisors, whose sum is σ = 21010533402518. Its totient is φ = 21010533402516.

The previous prime is 21010533402457. The next prime is 21010533402541. The reversal of 21010533402517 is 71520433501012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 16341070523281 + 4669462879236 = 4042409^2 + 2160894^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21010533402517 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21010533402017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505266701258 + 10505266701259.

It is an arithmetic number, because the mean of its divisors is an integer number (10505266701259).

Almost surely, 2^{21010533402517} is an apocalyptic number.

It is an amenable number.

21010533402517 is a deficient number, since it is larger than the sum of its proper divisors (1).

21010533402517 is an equidigital number, since it uses as much as digits as its factorization.

21010533402517 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25200, while the sum is 34.

Adding to 21010533402517 its reverse (71520433501012), we get a palindrome (92530966903529).

The spelling of 21010533402517 in words is "twenty-one trillion, ten billion, five hundred thirty-three million, four hundred two thousand, five hundred seventeen".