1006561516661 has 8 divisors (see below), whose sum is σ = 1008029105664. Its totient is φ = 1005094442160.

The previous prime is 1006561516621. The next prime is 1006561516691. The reversal of 1006561516661 is 1666151656001.

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

It is a cyclic number.

It is not a de Polignac number, because 1006561516661 - 2³⁸ = 731683609717 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1006561516621) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3877616 + ... + 4129046.

It is an arithmetic number, because the mean of its divisors is an integer number (126003638208).

Almost surely, 2^{1006561516661} is an apocalyptic number.

It is an amenable number.

1006561516661 is a deficient number, since it is larger than the sum of its proper divisors (1467589003).

1006561516661 is an equidigital number, since it uses as much as digits as its factorization.

1006561516661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 257251.

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

The spelling of 1006561516661 in words is "one trillion, six billion, five hundred sixty-one million, five hundred sixteen thousand, six hundred sixty-one".