166101221 has 8 divisors (see below), whose sum is σ = 195140064. Its totient is φ = 139385520.

The previous prime is 166101179. The next prime is 166101233. The reversal of 166101221 is 122101661.

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 166101221 - 2⁶ = 166101157 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 166101193 and 166101202.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (166101281) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 580631 + ... + 580916.

It is an arithmetic number, because the mean of its divisors is an integer number (24392508).

Almost surely, 2^166101221 is an apocalyptic number.

166101221 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

166101221 is a deficient number, since it is larger than the sum of its proper divisors (29038843).

166101221 is a wasteful number, since it uses less digits than its factorization.

166101221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1161571.

The product of its (nonzero) digits is 144, while the sum is 20.

The square root of 166101221 is about 12888.0262647156. The cubic root of 166101221 is about 549.6981495205.

Adding to 166101221 its reverse (122101661), we get a palindrome (288202882).

The spelling of 166101221 in words is "one hundred sixty-six million, one hundred one thousand, two hundred twenty-one".