66658466485661 has 2 divisors, whose sum is σ = 66658466485662. Its totient is φ = 66658466485660.

The previous prime is 66658466485651. The next prime is 66658466485717. The reversal of 66658466485661 is 16658466485666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 63360501524761 + 3297964960900 = 7959931^2 + 1816030^2 .

It is a cyclic number.

It is not a de Polignac number, because 66658466485661 - 2¹⁰ = 66658466484637 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66658466485651) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33329233242830 + 33329233242831.

It is an arithmetic number, because the mean of its divisors is an integer number (33329233242831).

Almost surely, 2^{66658466485661} is an apocalyptic number.

It is an amenable number.

66658466485661 is a deficient number, since it is larger than the sum of its proper divisors (1).

66658466485661 is an equidigital number, since it uses as much as digits as its factorization.

66658466485661 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7166361600, while the sum is 77.

The spelling of 66658466485661 in words is "sixty-six trillion, six hundred fifty-eight billion, four hundred sixty-six million, four hundred eighty-five thousand, six hundred sixty-one".