21010200173 has 2 divisors, whose sum is σ = 21010200174. Its totient is φ = 21010200172.

The previous prime is 21010200161. The next prime is 21010200181. The reversal of 21010200173 is 37100201012.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17025813289 + 3984386884 = 130483^2 + 63122^2 .

It is a cyclic number.

It is not a de Polignac number, because 21010200173 - 2⁶ = 21010200109 is a prime.

It is a super-2 number, since 2×21010200173² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21010200473) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505100086 + 10505100087.

It is an arithmetic number, because the mean of its divisors is an integer number (10505100087).

Almost surely, 2^21010200173 is an apocalyptic number.

It is an amenable number.

21010200173 is a deficient number, since it is larger than the sum of its proper divisors (1).

21010200173 is an equidigital number, since it uses as much as digits as its factorization.

21010200173 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 84, while the sum is 17.

Adding to 21010200173 its reverse (37100201012), we get a palindrome (58110401185).

The spelling of 21010200173 in words is "twenty-one billion, ten million, two hundred thousand, one hundred seventy-three".