168898787898989 has 4 divisors (see below), whose sum is σ = 168983364159324. Its totient is φ = 168814211638656.

The previous prime is 168898787898959. The next prime is 168898787899019. The reversal of 168898787898989 is 989898787898861.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is an interprime number because it is at equal distance from previous prime (168898787898959) and next prime (168898787899019).

It can be written as a sum of positive squares in 2 ways, for example, as 88365358081225 + 80533429817764 = 9400285^2 + 8974042^2 .

It is a cyclic number.

It is not a de Polignac number, because 168898787898989 - 2⁴⁰ = 167799276271213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (168898787898959) 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 in 3 ways as a sum of consecutive naturals, for example, 42288127172 + ... + 42288131165.

It is an arithmetic number, because the mean of its divisors is an integer number (42245841039831).

Almost surely, 2^{168898787898989} is an apocalyptic number.

It is an amenable number.

168898787898989 is a deficient number, since it is larger than the sum of its proper divisors (84576260335).

168898787898989 is an equidigital number, since it uses as much as digits as its factorization.

168898787898989 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 84576260334.

The product of its digits is 4045267795968, while the sum is 113.

The spelling of 168898787898989 in words is "one hundred sixty-eight trillion, eight hundred ninety-eight billion, seven hundred eighty-seven million, eight hundred ninety-eight thousand, nine hundred eighty-nine".