171072221 has 2 divisors, whose sum is σ = 171072222. Its totient is φ = 171072220.

The previous prime is 171072203. The next prime is 171072227. The reversal of 171072221 is 122270171.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 147355321 + 23716900 = 12139^2 + 4870^2 .

It is a cyclic number.

It is not a de Polignac number, because 171072221 - 2¹⁴ = 171055837 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (171072227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 85536110 + 85536111.

It is an arithmetic number, because the mean of its divisors is an integer number (85536111).

Almost surely, 2^171072221 is an apocalyptic number.

It is an amenable number.

171072221 is a deficient number, since it is larger than the sum of its proper divisors (1).

171072221 is an equidigital number, since it uses as much as digits as its factorization.

171072221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 392, while the sum is 23.

The square root of 171072221 is about 13079.4579780662. The cubic root of 171072221 is about 555.1280401498.

The spelling of 171072221 in words is "one hundred seventy-one million, seventy-two thousand, two hundred twenty-one".