21023020202521 has 2 divisors, whose sum is σ = 21023020202522. Its totient is φ = 21023020202520.

The previous prime is 21023020202501. The next prime is 21023020202537. The reversal of 21023020202521 is 12520202032012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21019657478400 + 3362724121 = 4584720^2 + 57989^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21023020202521 is a prime.

It is a super-2 number, since 2×21023020202521² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21023020202492 and 21023020202501.

It is not a weakly prime, because it can be changed into another prime (21023020202501) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10511510101260 + 10511510101261.

It is an arithmetic number, because the mean of its divisors is an integer number (10511510101261).

Almost surely, 2^{21023020202521} is an apocalyptic number.

It is an amenable number.

21023020202521 is a deficient number, since it is larger than the sum of its proper divisors (1).

21023020202521 is an equidigital number, since it uses as much as digits as its factorization.

21023020202521 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 960, while the sum is 22.

Adding to 21023020202521 its reverse (12520202032012), we get a palindrome (33543222234533).

The spelling of 21023020202521 in words is "twenty-one trillion, twenty-three billion, twenty million, two hundred two thousand, five hundred twenty-one".