166538 has 4 divisors (see below), whose sum is σ = 249810. Its totient is φ = 83268.

The previous prime is 166487. The next prime is 166541. The reversal of 166538 is 835661.

166538 is nontrivially palindromic in base 4.

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

It can be written as a sum of positive squares in only one way, i.e., 100489 + 66049 = 317^2 + 257^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 166538.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 166538.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 41633 + ... + 41636.

2¹⁶⁶⁵³⁸ is an apocalyptic number.

166538 is a deficient number, since it is larger than the sum of its proper divisors (83272).

166538 is an equidigital number, since it uses as much as digits as its factorization.

166538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 83271.

The product of its digits is 4320, while the sum is 29.

The square root of 166538 is about 408.0906761983. The cubic root of 166538 is about 55.0179555700.

It can be divided in two parts, 16653 and 8, that added together give a palindrome (16661).

The spelling of 166538 in words is "one hundred sixty-six thousand, five hundred thirty-eight".