181966231 has 2 divisors, whose sum is σ = 181966232. Its totient is φ = 181966230.

The previous prime is 181966229. The next prime is 181966247. The reversal of 181966231 is 132669181.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 181966231 - 2¹ = 181966229 is a prime.

It is a super-2 number, since 2×181966231² = 66223418448690722, which contains 22 as substring.

Together with 181966229, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (181964231) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90983115 + 90983116.

It is an arithmetic number, because the mean of its divisors is an integer number (90983116).

Almost surely, 2^181966231 is an apocalyptic number.

181966231 is the 8532-nd centered pentagonal number.

181966231 is a deficient number, since it is larger than the sum of its proper divisors (1).

181966231 is an equidigital number, since it uses as much as digits as its factorization.

181966231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 15552, while the sum is 37.

The square root of 181966231 is about 13489.4859427630. The cubic root of 181966231 is about 566.6700590723.

The spelling of 181966231 in words is "one hundred eighty-one million, nine hundred sixty-six thousand, two hundred thirty-one".