166523321 has 4 divisors (see below), whose sum is σ = 166700112. Its totient is φ = 166346532.

The previous prime is 166523317. The next prime is 166523323. The reversal of 166523321 is 123325661.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 166523321 - 2² = 166523317 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166523323) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 86975 + ... + 88868.

It is an arithmetic number, because the mean of its divisors is an integer number (41675028).

Almost surely, 2^166523321 is an apocalyptic number.

It is an amenable number.

166523321 is a deficient number, since it is larger than the sum of its proper divisors (176791).

166523321 is an equidigital number, since it uses as much as digits as its factorization.

166523321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 176790.

The product of its digits is 6480, while the sum is 29.

The square root of 166523321 is about 12904.3915393171. The cubic root of 166523321 is about 550.1633905746.

Adding to 166523321 its reverse (123325661), we get a palindrome (289848982).

The spelling of 166523321 in words is "one hundred sixty-six million, five hundred twenty-three thousand, three hundred twenty-one".