166312321 has 6 divisors (see below), whose sum is σ = 193465410. Its totient is φ = 142553376.

The previous prime is 166312313. The next prime is 166312331. The reversal of 166312321 is 123213661.

166312321 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 163200625 + 3111696 = 12775^2 + 1764^2 .

It is not a de Polignac number, because 166312321 - 2³ = 166312313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166312331) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1697016 + ... + 1697113.

It is an arithmetic number, because the mean of its divisors is an integer number (32244235).

Almost surely, 2^166312321 is an apocalyptic number.

It is an amenable number.

166312321 is a deficient number, since it is larger than the sum of its proper divisors (27153089).

166312321 is an equidigital number, since it uses as much as digits as its factorization.

166312321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3394143 (or 3394136 counting only the distinct ones).

The product of its digits is 1296, while the sum is 25.

The square root of 166312321 is about 12896.2134365092. The cubic root of 166312321 is about 549.9309235562.

Adding to 166312321 its reverse (123213661), we get a palindrome (289525982).

The spelling of 166312321 in words is "one hundred sixty-six million, three hundred twelve thousand, three hundred twenty-one".