181862221 has 2 divisors, whose sum is σ = 181862222. Its totient is φ = 181862220.

The previous prime is 181862207. The next prime is 181862227. The reversal of 181862221 is 122268181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 110544196 + 71318025 = 10514^2 + 8445^2 .

It is a cyclic number.

It is not a de Polignac number, because 181862221 - 2⁵ = 181862189 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (181862227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90931110 + 90931111.

It is an arithmetic number, because the mean of its divisors is an integer number (90931111).

Almost surely, 2^181862221 is an apocalyptic number.

It is an amenable number.

181862221 is a deficient number, since it is larger than the sum of its proper divisors (1).

181862221 is an equidigital number, since it uses as much as digits as its factorization.

181862221 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3072, while the sum is 31.

The square root of 181862221 is about 13485.6301669592. The cubic root of 181862221 is about 566.5620709294.

The spelling of 181862221 in words is "one hundred eighty-one million, eight hundred sixty-two thousand, two hundred twenty-one".