1100001091661 has 2 divisors, whose sum is σ = 1100001091662. Its totient is φ = 1100001091660.

The previous prime is 1100001091627. The next prime is 1100001091663. The reversal of 1100001091661 is 1661901000011.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 918350389636 + 181650702025 = 958306^2 + 426205^2 .

It is a cyclic number.

It is not a de Polignac number, because 1100001091661 - 2¹⁰ = 1100001090637 is a prime.

Together with 1100001091663, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1100001091661.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1100001091663) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 550000545830 + 550000545831.

It is an arithmetic number, because the mean of its divisors is an integer number (550000545831).

Almost surely, 2^{1100001091661} is an apocalyptic number.

It is an amenable number.

1100001091661 is a deficient number, since it is larger than the sum of its proper divisors (1).

1100001091661 is an equidigital number, since it uses as much as digits as its factorization.

1100001091661 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 324, while the sum is 26.

Adding to 1100001091661 its reverse (1661901000011), we get a palindrome (2761902091672).

The spelling of 1100001091661 in words is "one trillion, one hundred billion, one million, ninety-one thousand, six hundred sixty-one".