168023021 has 4 divisors (see below), whose sum is σ = 168346044. Its totient is φ = 167700000.

The previous prime is 168023017. The next prime is 168023029. The reversal of 168023021 is 120320861.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 120320861 = 3863 ⋅31147.

It can be written as a sum of positive squares in 2 ways, for example, as 32649796 + 135373225 = 5714^2 + 11635^2 .

It is a cyclic number.

It is not a de Polignac number, because 168023021 - 2² = 168023017 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 (168023029) 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, 160730 + ... + 161771.

It is an arithmetic number, because the mean of its divisors is an integer number (42086511).

Almost surely, 2^168023021 is an apocalyptic number.

It is an amenable number.

168023021 is a deficient number, since it is larger than the sum of its proper divisors (323023).

168023021 is an equidigital number, since it uses as much as digits as its factorization.

168023021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 323022.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 168023021 is about 12962.3694207502. The cubic root of 168023021 is about 551.8100377733.

Adding to 168023021 its reverse (120320861), we get a palindrome (288343882).

The spelling of 168023021 in words is "one hundred sixty-eight million, twenty-three thousand, twenty-one".