21530650563517 has 2 divisors, whose sum is σ = 21530650563518. Its totient is φ = 21530650563516.

The previous prime is 21530650563503. The next prime is 21530650563637. The reversal of 21530650563517 is 71536505603512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18702908998596 + 2827741564921 = 4324686^2 + 1681589^2 .

It is a cyclic number.

It is not a de Polignac number, because 21530650563517 - 2¹⁵ = 21530650530749 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21530650563017) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10765325281758 + 10765325281759.

It is an arithmetic number, because the mean of its divisors is an integer number (10765325281759).

Almost surely, 2^{21530650563517} is an apocalyptic number.

It is an amenable number.

21530650563517 is a deficient number, since it is larger than the sum of its proper divisors (1).

21530650563517 is an equidigital number, since it uses as much as digits as its factorization.

21530650563517 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2835000, while the sum is 49.

The spelling of 21530650563517 in words is "twenty-one trillion, five hundred thirty billion, six hundred fifty million, five hundred sixty-three thousand, five hundred seventeen".