21100120212173 has 2 divisors, whose sum is σ = 21100120212174. Its totient is φ = 21100120212172.

The previous prime is 21100120212169. The next prime is 21100120212221. The reversal of 21100120212173 is 37121202100112.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19863404958244 + 1236715253929 = 4456838^2 + 1112077^2 .

It is a cyclic number.

It is not a de Polignac number, because 21100120212173 - 2² = 21100120212169 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21100120212973) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550060106086 + 10550060106087.

It is an arithmetic number, because the mean of its divisors is an integer number (10550060106087).

Almost surely, 2^{21100120212173} is an apocalyptic number.

It is an amenable number.

21100120212173 is a deficient number, since it is larger than the sum of its proper divisors (1).

21100120212173 is an equidigital number, since it uses as much as digits as its factorization.

21100120212173 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 336, while the sum is 23.

Adding to 21100120212173 its reverse (37121202100112), we get a palindrome (58221322312285).

The spelling of 21100120212173 in words is "twenty-one trillion, one hundred billion, one hundred twenty million, two hundred twelve thousand, one hundred seventy-three".