166305121 has 4 divisors (see below), whose sum is σ = 170799892. Its totient is φ = 161810352.

The previous prime is 166305091. The next prime is 166305127. The reversal of 166305121 is 121503661.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 121503661 = 571 ⋅212791.

It can be written as a sum of positive squares in 2 ways, for example, as 119574225 + 46730896 = 10935^2 + 6836^2 .

It is a cyclic number.

It is not a de Polignac number, because 166305121 - 2⁵ = 166305089 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (166305127) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2247330 + ... + 2247403.

It is an arithmetic number, because the mean of its divisors is an integer number (42699973).

Almost surely, 2^166305121 is an apocalyptic number.

It is an amenable number.

166305121 is a deficient number, since it is larger than the sum of its proper divisors (4494771).

166305121 is an equidigital number, since it uses as much as digits as its factorization.

166305121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4494770.

The product of its (nonzero) digits is 1080, while the sum is 25.

The square root of 166305121 is about 12895.9342817804. The cubic root of 166305121 is about 549.9229875641.

Adding to 166305121 its reverse (121503661), we get a palindrome (287808782).

It can be divided in two parts, 16 and 6305121, that multiplied together give a square (100881936 = 10044²).

The spelling of 166305121 in words is "one hundred sixty-six million, three hundred five thousand, one hundred twenty-one".