181923881 has 2 divisors, whose sum is σ = 181923882. Its totient is φ = 181923880.

The previous prime is 181923839. The next prime is 181923883. The reversal of 181923881 is 188329181.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 181818256 + 105625 = 13484^2 + 325^2 .

It is an emirp because it is prime and its reverse (188329181) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 181923881 - 2¹⁰ = 181922857 is a prime.

It is a super-2 number, since 2×181923881² = 66192596956204322, which contains 22 as substring.

It is a Sophie Germain prime.

Together with 181923883, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (181923883) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90961940 + 90961941.

It is an arithmetic number, because the mean of its divisors is an integer number (90961941).

Almost surely, 2^181923881 is an apocalyptic number.

It is an amenable number.

181923881 is a deficient number, since it is larger than the sum of its proper divisors (1).

181923881 is an equidigital number, since it uses as much as digits as its factorization.

181923881 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 27648, while the sum is 41.

The square root of 181923881 is about 13487.9161103560. The cubic root of 181923881 is about 566.6260942501.

The spelling of 181923881 in words is "one hundred eighty-one million, nine hundred twenty-three thousand, eight hundred eighty-one".