181310221 has 2 divisors, whose sum is σ = 181310222. Its totient is φ = 181310220.

The previous prime is 181310197. The next prime is 181310243. The reversal of 181310221 is 122013181.

181310221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 179265321 + 2044900 = 13389^2 + 1430^2 .

It is a cyclic number.

It is not a de Polignac number, because 181310221 - 2⁷ = 181310093 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 (181310821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90655110 + 90655111.

It is an arithmetic number, because the mean of its divisors is an integer number (90655111).

Almost surely, 2^181310221 is an apocalyptic number.

It is an amenable number.

181310221 is a deficient number, since it is larger than the sum of its proper divisors (1).

181310221 is an equidigital number, since it uses as much as digits as its factorization.

181310221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 96, while the sum is 19.

The square root of 181310221 is about 13465.1483838835. The cubic root of 181310221 is about 565.9882680167.

The spelling of 181310221 in words is "one hundred eighty-one million, three hundred ten thousand, two hundred twenty-one".