166533621 has 4 divisors (see below), whose sum is σ = 222044832. Its totient is φ = 111022412.

The previous prime is 166533617. The next prime is 166533629. The reversal of 166533621 is 126335661.

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 166533621 - 2² = 166533617 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166533629) 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, 27755601 + ... + 27755606.

It is an arithmetic number, because the mean of its divisors is an integer number (55511208).

Almost surely, 2^166533621 is an apocalyptic number.

It is an amenable number.

166533621 is a deficient number, since it is larger than the sum of its proper divisors (55511211).

166533621 is an equidigital number, since it uses as much as digits as its factorization.

166533621 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 55511210.

The product of its digits is 19440, while the sum is 33.

The square root of 166533621 is about 12904.7906220907. The cubic root of 166533621 is about 550.1747334625.

The spelling of 166533621 in words is "one hundred sixty-six million, five hundred thirty-three thousand, six hundred twenty-one".