168428989 has 4 divisors (see below), whose sum is σ = 168740860. Its totient is φ = 168117120.

The previous prime is 168428959. The next prime is 168429017. The reversal of 168428989 is 989824861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 989824861 = 1049 ⋅943589.

It can be written as a sum of positive squares in 2 ways, for example, as 109369764 + 59059225 = 10458^2 + 7685^2 .

It is a cyclic number.

It is not a de Polignac number, because 168428989 - 2¹¹ = 168426941 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 (168428929) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 155124 + ... + 156205.

It is an arithmetic number, because the mean of its divisors is an integer number (42185215).

Almost surely, 2^168428989 is an apocalyptic number.

It is an amenable number.

168428989 is a deficient number, since it is larger than the sum of its proper divisors (311871).

168428989 is an equidigital number, since it uses as much as digits as its factorization.

168428989 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311870.

The product of its digits is 1990656, while the sum is 55.

The square root of 168428989 is about 12978.0194559879. The cubic root of 168428989 is about 552.2540980346.

The spelling of 168428989 in words is "one hundred sixty-eight million, four hundred twenty-eight thousand, nine hundred eighty-nine".