2166121 has 2 divisors, whose sum is σ = 2166122. Its totient is φ = 2166120.

The previous prime is 2166119. The next prime is 2166127. The reversal of 2166121 is 1216612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1125721 + 1040400 = 1061^2 + 1020^2 .

It is a cyclic number.

It is not a de Polignac number, because 2166121 - 2¹ = 2166119 is a prime.

Together with 2166119, it forms a pair of twin primes.

It is an Ulam number.

2166121 is a lucky number.

It is equal to p₁₆₀₃₇₂ and since 2166121 and 160372 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (2166127) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1083060 + 1083061.

It is an arithmetic number, because the mean of its divisors is an integer number (1083061).

2^2166121 is an apocalyptic number.

It is an amenable number.

2166121 is a deficient number, since it is larger than the sum of its proper divisors (1).

2166121 is an equidigital number, since it uses as much as digits as its factorization.

2166121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 144, while the sum is 19.

The square root of 2166121 is about 1471.7747789659. The cubic root of 2166121 is about 129.3880708242.

The spelling of 2166121 in words is "two million, one hundred sixty-six thousand, one hundred twenty-one".