21220001202173 has 2 divisors, whose sum is σ = 21220001202174. Its totient is φ = 21220001202172.

The previous prime is 21220001202163. The next prime is 21220001202217. The reversal of 21220001202173 is 37120210002212.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21172118134489 + 47883067684 = 4601317^2 + 218822^2 .

It is a cyclic number.

It is not a de Polignac number, because 21220001202173 - 2⁴ = 21220001202157 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21220001202143) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610000601086 + 10610000601087.

It is an arithmetic number, because the mean of its divisors is an integer number (10610000601087).

Almost surely, 2^{21220001202173} is an apocalyptic number.

It is an amenable number.

21220001202173 is a deficient number, since it is larger than the sum of its proper divisors (1).

21220001202173 is an equidigital number, since it uses as much as digits as its factorization.

21220001202173 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 672, while the sum is 23.

Adding to 21220001202173 its reverse (37120210002212), we get a palindrome (58340211204385).

The spelling of 21220001202173 in words is "twenty-one trillion, two hundred twenty billion, one million, two hundred two thousand, one hundred seventy-three".