21002003002021 has 2 divisors, whose sum is σ = 21002003002022. Its totient is φ = 21002003002020.

The previous prime is 21002003001971. The next prime is 21002003002027. The reversal of 21002003002021 is 12020030020012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20556294549025 + 445708452996 = 4533905^2 + 667614^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21002003002021 is a prime.

It is a super-2 number, since 2×21002003002021² (a number of 27 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21002003001992 and 21002003002010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21002003002027) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501001501010 + 10501001501011.

It is an arithmetic number, because the mean of its divisors is an integer number (10501001501011).

Almost surely, 2^{21002003002021} is an apocalyptic number.

It is an amenable number.

21002003002021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002003002021 is an equidigital number, since it uses as much as digits as its factorization.

21002003002021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 48, while the sum is 13.

Adding to 21002003002021 its reverse (12020030020012), we get a palindrome (33022033022033).

The spelling of 21002003002021 in words is "twenty-one trillion, two billion, three million, two thousand, twenty-one".