21530534314321 has 2 divisors, whose sum is σ = 21530534314322. Its totient is φ = 21530534314320.

The previous prime is 21530534314291. The next prime is 21530534314379. The reversal of 21530534314321 is 12341343503512.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 12437535302721 + 9092999011600 = 3526689^2 + 3015460^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21530534314321 is a prime.

It is not a weakly prime, because it can be changed into another prime (21530534312321) 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, 10765267157160 + 10765267157161.

It is an arithmetic number, because the mean of its divisors is an integer number (10765267157161).

Almost surely, 2^{21530534314321} is an apocalyptic number.

It is an amenable number.

21530534314321 is a deficient number, since it is larger than the sum of its proper divisors (1).

21530534314321 is an equidigital number, since it uses as much as digits as its factorization.

21530534314321 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 129600, while the sum is 37.

Adding to 21530534314321 its reverse (12341343503512), we get a palindrome (33871877817833).

The spelling of 21530534314321 in words is "twenty-one trillion, five hundred thirty billion, five hundred thirty-four million, three hundred fourteen thousand, three hundred twenty-one".