181861165973 has 2 divisors, whose sum is σ = 181861165974. Its totient is φ = 181861165972.

The previous prime is 181861165961. The next prime is 181861165979. The reversal of 181861165973 is 379561168181.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 177326894404 + 4534271569 = 421102^2 + 67337^2 .

It is a cyclic number.

It is not a de Polignac number, because 181861165973 - 2¹⁰ = 181861164949 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (181861165979) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90930582986 + 90930582987.

It is an arithmetic number, because the mean of its divisors is an integer number (90930582987).

Almost surely, 2^181861165973 is an apocalyptic number.

It is an amenable number.

181861165973 is a deficient number, since it is larger than the sum of its proper divisors (1).

181861165973 is an equidigital number, since it uses as much as digits as its factorization.

181861165973 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2177280, while the sum is 56.

The spelling of 181861165973 in words is "one hundred eighty-one billion, eight hundred sixty-one million, one hundred sixty-five thousand, nine hundred seventy-three".