21530545202357 has 2 divisors, whose sum is σ = 21530545202358. Its totient is φ = 21530545202356.

The previous prime is 21530545202323. The next prime is 21530545202359. The reversal of 21530545202357 is 75320254503512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 11860646957041 + 9669898245316 = 3443929^2 + 3109646^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21530545202357 is a prime.

Together with 21530545202359, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21530545202359) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10765272601178 + 10765272601179.

It is an arithmetic number, because the mean of its divisors is an integer number (10765272601179).

Almost surely, 2^{21530545202357} is an apocalyptic number.

It is an amenable number.

21530545202357 is a deficient number, since it is larger than the sum of its proper divisors (1).

21530545202357 is an equidigital number, since it uses as much as digits as its factorization.

21530545202357 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1260000, while the sum is 44.

Adding to 21530545202357 its reverse (75320254503512), we get a palindrome (96850799705869).

The spelling of 21530545202357 in words is "twenty-one trillion, five hundred thirty billion, five hundred forty-five million, two hundred two thousand, three hundred fifty-seven".