166412321 has 4 divisors (see below), whose sum is σ = 166439700. Its totient is φ = 166384944.

The previous prime is 166412297. The next prime is 166412339. The reversal of 166412321 is 123214661.

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

It can be written as a sum of positive squares in 2 ways, for example, as 65691025 + 100721296 = 8105^2 + 10036^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-166412321 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (166412341) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 26 + ... + 18243.

It is an arithmetic number, because the mean of its divisors is an integer number (41609925).

Almost surely, 2^166412321 is an apocalyptic number.

It is an amenable number.

166412321 is a deficient number, since it is larger than the sum of its proper divisors (27379).

166412321 is an equidigital number, since it uses as much as digits as its factorization.

166412321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27378.

The product of its digits is 1728, while the sum is 26.

The square root of 166412321 is about 12900.0899609266. The cubic root of 166412321 is about 550.0411219942.

Adding to 166412321 its reverse (123214661), we get a palindrome (289626982).

The spelling of 166412321 in words is "one hundred sixty-six million, four hundred twelve thousand, three hundred twenty-one".