168723021809 has 2 divisors, whose sum is σ = 168723021810. Its totient is φ = 168723021808.

The previous prime is 168723021767. The next prime is 168723021851. The reversal of 168723021809 is 908120327861.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (168723021767) and next prime (168723021851).

It can be written as a sum of positive squares in only one way, i.e., 155494571584 + 13228450225 = 394328^2 + 115015^2 .

It is a cyclic number.

It is not a de Polignac number, because 168723021809 - 2¹⁶ = 168722956273 is a prime.

It is a super-3 number, since 3×168723021809³ (a number of 35 digits) contains 333 as substring.

It is not a weakly prime, because it can be changed into another prime (168723221809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 84361510904 + 84361510905.

It is an arithmetic number, because the mean of its divisors is an integer number (84361510905).

Almost surely, 2^168723021809 is an apocalyptic number.

It is an amenable number.

168723021809 is a deficient number, since it is larger than the sum of its proper divisors (1).

168723021809 is an equidigital number, since it uses as much as digits as its factorization.

168723021809 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 290304, while the sum is 47.

The spelling of 168723021809 in words is "one hundred sixty-eight billion, seven hundred twenty-three million, twenty-one thousand, eight hundred nine".