1665666576449 has 2 divisors, whose sum is σ = 1665666576450. Its totient is φ = 1665666576448.

The previous prime is 1665666576443. The next prime is 1665666576479. The reversal of 1665666576449 is 9446756665661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1569670708225 + 95995868224 = 1252865^2 + 309832^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1665666576449 is a prime.

It is a super-2 number, since 2×1665666576449² (a number of 25 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1665666576443) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 832833288224 + 832833288225.

It is an arithmetic number, because the mean of its divisors is an integer number (832833288225).

Almost surely, 2^{1665666576449} is an apocalyptic number.

It is an amenable number.

1665666576449 is a deficient number, since it is larger than the sum of its proper divisors (1).

1665666576449 is an equidigital number, since it uses as much as digits as its factorization.

1665666576449 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1175731200, while the sum is 71.

The spelling of 1665666576449 in words is "one trillion, six hundred sixty-five billion, six hundred sixty-six million, five hundred seventy-six thousand, four hundred forty-nine".