181222181 has 4 divisors (see below), whose sum is σ = 207111072. Its totient is φ = 155333292.

The previous prime is 181222141. The next prime is 181222183.

181222181 is nontrivially palindromic in base 10.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 181222181 - 2¹⁸ = 180960037 is a prime.

It is a super-2 number, since 2×181222181² = 65682957772793522, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 181222181.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (181222183) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12944435 + ... + 12944448.

It is an arithmetic number, because the mean of its divisors is an integer number (51777768).

Almost surely, 2^181222181 is an apocalyptic number.

It is an amenable number.

181222181 is a deficient number, since it is larger than the sum of its proper divisors (25888891).

181222181 is an equidigital number, since it uses as much as digits as its factorization.

181222181 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25888890.

The product of its digits is 512, while the sum is 26.

The square root of 181222181 is about 13461.8788064668. The cubic root of 181222181 is about 565.8966429659.

The spelling of 181222181 in words is "one hundred eighty-one million, two hundred twenty-two thousand, one hundred eighty-one".