166554221 has 8 divisors (see below), whose sum is σ = 172525080. Its totient is φ = 160598592.

The previous prime is 166554211. The next prime is 166554233. The reversal of 166554221 is 122455661.

It can be written as a sum of positive squares in 4 ways, for example, as 36844900 + 129709321 = 6070^2 + 11389^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 166554221 - 2¹⁰ = 166553197 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166554211) 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 7 ways as a sum of consecutive naturals, for example, 21371 + ... + 28103.

It is an arithmetic number, because the mean of its divisors is an integer number (21565635).

Almost surely, 2^166554221 is an apocalyptic number.

It is an amenable number.

166554221 is a deficient number, since it is larger than the sum of its proper divisors (5970859).

166554221 is an equidigital number, since it uses as much as digits as its factorization.

166554221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7615.

The product of its digits is 14400, while the sum is 32.

The square root of 166554221 is about 12905.5887506150. The cubic root of 166554221 is about 550.1974178353.

The spelling of 166554221 in words is "one hundred sixty-six million, five hundred fifty-four thousand, two hundred twenty-one".