21000200121021 has 12 divisors (see below), whose sum is σ = 30777152794976. Its totient is φ = 12727394012520.

The previous prime is 21000200120981. The next prime is 21000200121083. The reversal of 21000200121021 is 12012100200012.

It is not a de Polignac number, because 21000200121021 - 2¹⁷ = 21000199989949 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21000200120988 and 21000200121006.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21000200121221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 28925895121 + ... + 28925895846.

Almost surely, 2^{21000200121021} is an apocalyptic number.

It is an amenable number.

21000200121021 is a deficient number, since it is larger than the sum of its proper divisors (9776952673955).

21000200121021 is a wasteful number, since it uses less digits than its factorization.

21000200121021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 57851790992 (or 57851790981 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21000200121021 its reverse (12012100200012), we get a palindrome (33012300321033).

The spelling of 21000200121021 in words is "twenty-one trillion, two hundred million, one hundred twenty-one thousand, twenty-one".