21001122101021 has 2 divisors, whose sum is σ = 21001122101022. Its totient is φ = 21001122101020.

The previous prime is 21001122100951. The next prime is 21001122101087. The reversal of 21001122101021 is 12010122110012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19050728301796 + 1950393799225 = 4364714^2 + 1396565^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21001122101021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21001122100987 and 21001122101005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21001121101021) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500561050510 + 10500561050511.

It is an arithmetic number, because the mean of its divisors is an integer number (10500561050511).

Almost surely, 2^{21001122101021} is an apocalyptic number.

It is an amenable number.

21001122101021 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001122101021 is an equidigital number, since it uses as much as digits as its factorization.

21001122101021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21001122101021 its reverse (12010122110012), we get a palindrome (33011244211033).

The spelling of 21001122101021 in words is "twenty-one trillion, one billion, one hundred twenty-two million, one hundred one thousand, twenty-one".