165819421089233 has 2 divisors, whose sum is σ = 165819421089234. Its totient is φ = 165819421089232.

The previous prime is 165819421089221. The next prime is 165819421089323. The reversal of 165819421089233 is 332980124918561.

Together with next prime (165819421089323) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 138285652098064 + 27533768991169 = 11759492^2 + 5247263^2 .

It is a cyclic number.

It is not a de Polignac number, because 165819421089233 - 2⁶ = 165819421089169 is a prime.

It is a super-2 number, since 2×165819421089233² (a number of 29 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (165819421019233) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 82909710544616 + 82909710544617.

It is an arithmetic number, because the mean of its divisors is an integer number (82909710544617).

Almost surely, 2^{165819421089233} is an apocalyptic number.

It is an amenable number.

165819421089233 is a deficient number, since it is larger than the sum of its proper divisors (1).

165819421089233 is an equidigital number, since it uses as much as digits as its factorization.

165819421089233 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 22394880, while the sum is 62.

The spelling of 165819421089233 in words is "one hundred sixty-five trillion, eight hundred nineteen billion, four hundred twenty-one million, eighty-nine thousand, two hundred thirty-three".