21010133120021 has 2 divisors, whose sum is σ = 21010133120022. Its totient is φ = 21010133120020.

The previous prime is 21010133120017. The next prime is 21010133120047. The reversal of 21010133120021 is 12002133101012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 15744714497521 + 5265418622500 = 3967961^2 + 2294650^2 .

It is a cyclic number.

It is not a de Polignac number, because 21010133120021 - 2² = 21010133120017 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21010133150021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505066560010 + 10505066560011.

It is an arithmetic number, because the mean of its divisors is an integer number (10505066560011).

Almost surely, 2^{21010133120021} is an apocalyptic number.

It is an amenable number.

21010133120021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21010133120021 is an equidigital number, since it uses as much as digits as its factorization.

21010133120021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 21010133120021 its reverse (12002133101012), we get a palindrome (33012266221033).

The spelling of 21010133120021 in words is "twenty-one trillion, ten billion, one hundred thirty-three million, one hundred twenty thousand, twenty-one".