1100166556661 has 2 divisors, whose sum is σ = 1100166556662. Its totient is φ = 1100166556660.

The previous prime is 1100166556649. The next prime is 1100166556717. The reversal of 1100166556661 is 1666556610011.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 828809952100 + 271356604561 = 910390^2 + 520919^2 .

It is an emirp because it is prime and its reverse (1666556610011) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1100166556661 - 2⁶ = 1100166556597 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1100166556631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 550083278330 + 550083278331.

It is an arithmetic number, because the mean of its divisors is an integer number (550083278331).

Almost surely, 2^{1100166556661} is an apocalyptic number.

It is an amenable number.

1100166556661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1100166556661 is an equidigital number, since it uses as much as digits as its factorization.

1100166556661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 194400, while the sum is 44.

The spelling of 1100166556661 in words is "one trillion, one hundred billion, one hundred sixty-six million, five hundred fifty-six thousand, six hundred sixty-one".