1661100665663 has 2 divisors, whose sum is σ = 1661100665664. Its totient is φ = 1661100665662.

The previous prime is 1661100665611. The next prime is 1661100665681. The reversal of 1661100665663 is 3665660011661.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1661100665663 - 2¹⁶ = 1661100600127 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1661100665363) 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, 830550332831 + 830550332832.

It is an arithmetic number, because the mean of its divisors is an integer number (830550332832).

Almost surely, 2^{1661100665663} is an apocalyptic number.

1661100665663 is a deficient number, since it is larger than the sum of its proper divisors (1).

1661100665663 is an equidigital number, since it uses as much as digits as its factorization.

1661100665663 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 699840, while the sum is 47.

The spelling of 1661100665663 in words is "one trillion, six hundred sixty-one billion, one hundred million, six hundred sixty-five thousand, six hundred sixty-three".