172205673221 has 2 divisors, whose sum is σ = 172205673222. Its totient is φ = 172205673220.

The previous prime is 172205673187. The next prime is 172205673247. The reversal of 172205673221 is 122376502271.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 158443802500 + 13761870721 = 398050^2 + 117311^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-172205673221 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (172205673251) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 86102836610 + 86102836611.

It is an arithmetic number, because the mean of its divisors is an integer number (86102836611).

Almost surely, 2^172205673221 is an apocalyptic number.

It is an amenable number.

172205673221 is a deficient number, since it is larger than the sum of its proper divisors (1).

172205673221 is an equidigital number, since it uses as much as digits as its factorization.

172205673221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 70560, while the sum is 38.

The spelling of 172205673221 in words is "one hundred seventy-two billion, two hundred five million, six hundred seventy-three thousand, two hundred twenty-one".