1666253752109 has 2 divisors, whose sum is σ = 1666253752110. Its totient is φ = 1666253752108.

The previous prime is 1666253752087. The next prime is 1666253752123. The reversal of 1666253752109 is 9012573526661.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1330343094025 + 335910658084 = 1153405^2 + 579578^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1666253752109 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1666253752159) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 833126876054 + 833126876055.

It is an arithmetic number, because the mean of its divisors is an integer number (833126876055).

Almost surely, 2^{1666253752109} is an apocalyptic number.

It is an amenable number.

1666253752109 is a deficient number, since it is larger than the sum of its proper divisors (1).

1666253752109 is an equidigital number, since it uses as much as digits as its factorization.

1666253752109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 4082400, while the sum is 53.

The spelling of 1666253752109 in words is "one trillion, six hundred sixty-six billion, two hundred fifty-three million, seven hundred fifty-two thousand, one hundred nine".