21002213201521 has 2 divisors, whose sum is σ = 21002213201522. Its totient is φ = 21002213201520.

The previous prime is 21002213201503. The next prime is 21002213201537. The reversal of 21002213201521 is 12510231220012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17272336000000 + 3729877201521 = 4156000^2 + 1931289^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002213201521 - 2⁹ = 21002213201009 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21002213201492 and 21002213201501.

It is not a weakly prime, because it can be changed into another prime (21002213201621) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501106600760 + 10501106600761.

It is an arithmetic number, because the mean of its divisors is an integer number (10501106600761).

Almost surely, 2^{21002213201521} is an apocalyptic number.

It is an amenable number.

21002213201521 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002213201521 is an equidigital number, since it uses as much as digits as its factorization.

21002213201521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 480, while the sum is 22.

Adding to 21002213201521 its reverse (12510231220012), we get a palindrome (33512444421533).

The spelling of 21002213201521 in words is "twenty-one trillion, two billion, two hundred thirteen million, two hundred one thousand, five hundred twenty-one".