171881221 has 2 divisors, whose sum is σ = 171881222. Its totient is φ = 171881220.

The previous prime is 171881207. The next prime is 171881257. The reversal of 171881221 is 122188171.

171881221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 166048996 + 5832225 = 12886^2 + 2415^2 .

It is a cyclic number.

It is not a de Polignac number, because 171881221 - 2⁵ = 171881189 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 (171881261) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 85940610 + 85940611.

It is an arithmetic number, because the mean of its divisors is an integer number (85940611).

Almost surely, 2^171881221 is an apocalyptic number.

It is an amenable number.

171881221 is a deficient number, since it is larger than the sum of its proper divisors (1).

171881221 is an equidigital number, since it uses as much as digits as its factorization.

171881221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1792, while the sum is 31.

The square root of 171881221 is about 13110.3478596107. The cubic root of 171881221 is about 556.0017306245.

The spelling of 171881221 in words is "one hundred seventy-one million, eight hundred eighty-one thousand, two hundred twenty-one".