1816121 has 2 divisors, whose sum is σ = 1816122. Its totient is φ = 1816120.

The previous prime is 1816117. The next prime is 1816141. The reversal of 1816121 is 1216181.

It is an a-pointer prime, because the next prime (1816141) can be obtained adding 1816121 to its sum of digits (20).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1290496 + 525625 = 1136^2 + 725^2 .

It is a cyclic number.

It is not a de Polignac number, because 1816121 - 2² = 1816117 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is an alternating number because its digits alternate between odd and even.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 1816093 and 1816102.

It is not a weakly prime, because it can be changed into another prime (1816141) 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 as a sum of consecutive naturals, namely, 908060 + 908061.

It is an arithmetic number, because the mean of its divisors is an integer number (908061).

2^1816121 is an apocalyptic number.

It is an amenable number.

1816121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1816121 is an equidigital number, since it uses as much as digits as its factorization.

1816121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 96, while the sum is 20.

The square root of 1816121 is about 1347.6353364319. The cubic root of 1816121 is about 122.0061136415.

The spelling of 1816121 in words is "one million, eight hundred sixteen thousand, one hundred twenty-one".