1660121 has 2 divisors, whose sum is σ = 1660122. Its totient is φ = 1660120.

The previous prime is 1660111. The next prime is 1660133. The reversal of 1660121 is 1210661.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1466521 + 193600 = 1211^2 + 440^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1660121 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1660121.

It is not a weakly prime, because it can be changed into another prime (1660111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 830060 + 830061.

It is an arithmetic number, because the mean of its divisors is an integer number (830061).

2^1660121 is an apocalyptic number.

It is an amenable number.

1660121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1660121 is an equidigital number, since it uses as much as digits as its factorization.

1660121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 1660121 is about 1288.4568289237. The cubic root of 1660121 is about 118.4076915885.

Adding to 1660121 its reverse (1210661), we get a palindrome (2870782).

The spelling of 1660121 in words is "one million, six hundred sixty thousand, one hundred twenty-one".