21521102353 has 2 divisors, whose sum is σ = 21521102354. Its totient is φ = 21521102352.

The previous prime is 21521102347. The next prime is 21521102387. The reversal of 21521102353 is 35320112512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17676234304 + 3844868049 = 132952^2 + 62007^2 .

It is a cyclic number.

It is not a de Polignac number, because 21521102353 - 2²⁹ = 20984231441 is a prime.

It is not a weakly prime, because it can be changed into another prime (21521108353) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10760551176 + 10760551177.

It is an arithmetic number, because the mean of its divisors is an integer number (10760551177).

Almost surely, 2^21521102353 is an apocalyptic number.

It is an amenable number.

21521102353 is a deficient number, since it is larger than the sum of its proper divisors (1).

21521102353 is an equidigital number, since it uses as much as digits as its factorization.

21521102353 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1800, while the sum is 25.

Adding to 21521102353 its reverse (35320112512), we get a palindrome (56841214865).

The spelling of 21521102353 in words is "twenty-one billion, five hundred twenty-one million, one hundred two thousand, three hundred fifty-three".