21102121011173 has 2 divisors, whose sum is σ = 21102121011174. Its totient is φ = 21102121011172.

The previous prime is 21102121011091. The next prime is 21102121011271. The reversal of 21102121011173 is 37111012120112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18301609129444 + 2800511881729 = 4278038^2 + 1673473^2 .

It is a cyclic number.

It is not a de Polignac number, because 21102121011173 - 2³⁶ = 21033401534437 is a prime.

It is a super-3 number, since 3×21102121011173³ (a number of 41 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21102121016173) 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, 10551060505586 + 10551060505587.

It is an arithmetic number, because the mean of its divisors is an integer number (10551060505587).

Almost surely, 2^{21102121011173} is an apocalyptic number.

It is an amenable number.

21102121011173 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102121011173 is an equidigital number, since it uses as much as digits as its factorization.

21102121011173 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 168, while the sum is 23.

Adding to 21102121011173 its reverse (37111012120112), we get a palindrome (58213133131285).

The spelling of 21102121011173 in words is "twenty-one trillion, one hundred two billion, one hundred twenty-one million, eleven thousand, one hundred seventy-three".