1011561101666 has 8 divisors (see below), whose sum is σ = 1545970740444. Its totient is φ = 496237521520.

The previous prime is 1011561101659. The next prime is 1011561101693. The reversal of 1011561101666 is 6661011651101.

It can be written as a sum of positive squares in 2 ways, for example, as 1002511575025 + 9049526641 = 1001255^2 + 95129^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4771514525 + ... + 4771514736.

Almost surely, 2^{1011561101666} is an apocalyptic number.

1011561101666 is a deficient number, since it is larger than the sum of its proper divisors (534409638778).

1011561101666 is an equidigital number, since it uses as much as digits as its factorization.

1011561101666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9543029316.

The product of its (nonzero) digits is 6480, while the sum is 35.

Adding to 1011561101666 its reverse (6661011651101), we get a palindrome (7672572752767).

The spelling of 1011561101666 in words is "one trillion, eleven billion, five hundred sixty-one million, one hundred one thousand, six hundred sixty-six".