181989067321 has 2 divisors, whose sum is σ = 181989067322. Its totient is φ = 181989067320.

The previous prime is 181989067279. The next prime is 181989067327. The reversal of 181989067321 is 123760989181.

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., 168891409296 + 13097658025 = 410964^2 + 114445^2 .

It is a cyclic number.

It is not a de Polignac number, because 181989067321 - 2⁷ = 181989067193 is a prime.

It is not a weakly prime, because it can be changed into another prime (181989067327) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 90994533660 + 90994533661.

It is an arithmetic number, because the mean of its divisors is an integer number (90994533661).

Almost surely, 2^181989067321 is an apocalyptic number.

It is an amenable number.

181989067321 is a deficient number, since it is larger than the sum of its proper divisors (1).

181989067321 is an equidigital number, since it uses as much as digits as its factorization.

181989067321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1306368, while the sum is 55.

The spelling of 181989067321 in words is "one hundred eighty-one billion, nine hundred eighty-nine million, sixty-seven thousand, three hundred twenty-one".