21010020010021 has 4 divisors (see below), whose sum is σ = 24011451440032. Its totient is φ = 18008588580012.

The previous prime is 21010020009991. The next prime is 21010020010127. The reversal of 21010020010021 is 12001002001012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21010020010021 - 2⁹ = 21010020009509 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010020110021) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1500715714995 + ... + 1500715715008.

It is an arithmetic number, because the mean of its divisors is an integer number (6002862860008).

Almost surely, 2^{21010020010021} is an apocalyptic number.

It is an amenable number.

21010020010021 is a deficient number, since it is larger than the sum of its proper divisors (3001431430011).

21010020010021 is an equidigital number, since it uses as much as digits as its factorization.

21010020010021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3001431430010.

The product of its (nonzero) digits is 8, while the sum is 10.

Adding to 21010020010021 its reverse (12001002001012), we get a palindrome (33011022011033).

The spelling of 21010020010021 in words is "twenty-one trillion, ten billion, twenty million, ten thousand, twenty-one".