1666744169 has 2 divisors, whose sum is σ = 1666744170. Its totient is φ = 1666744168.

The previous prime is 1666744139. The next prime is 1666744229. The reversal of 1666744169 is 9614476661.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1537580944 + 129163225 = 39212^2 + 11365^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1666744169 is a prime.

It is a super-2 number, since 2×1666744169² = 5556072249791001122, which 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 (1666744139) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833372084 + 833372085.

It is an arithmetic number, because the mean of its divisors is an integer number (833372085).

Almost surely, 2^1666744169 is an apocalyptic number.

It is an amenable number.

1666744169 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666744169 is an equidigital number, since it uses as much as digits as its factorization.

1666744169 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1306368, while the sum is 50.

The square root of 1666744169 is about 40825.7782412044. The cubic root of 1666744169 is about 1185.6494790472.

The spelling of 1666744169 in words is "one billion, six hundred sixty-six million, seven hundred forty-four thousand, one hundred sixty-nine".