1616661065561 has 8 divisors (see below), whose sum is σ = 1626381941184. Its totient is φ = 1606940669680.

The previous prime is 1616661065549. The next prime is 1616661065567. The reversal of 1616661065561 is 1655601666161.

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 1616661065561 - 2¹⁰ = 1616661064537 is a prime.

It is a super-2 number, since 2×1616661065561² (a number of 25 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1616661065567) 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 in 7 ways as a sum of consecutive naturals, for example, 8491826 + ... + 8680116.

It is an arithmetic number, because the mean of its divisors is an integer number (203297742648).

Almost surely, 2^{1616661065561} is an apocalyptic number.

It is an amenable number.

1616661065561 is a deficient number, since it is larger than the sum of its proper divisors (9720875623).

1616661065561 is a wasteful number, since it uses less digits than its factorization.

1616661065561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 239871.

The product of its (nonzero) digits is 1166400, while the sum is 50.

The spelling of 1616661065561 in words is "one trillion, six hundred sixteen billion, six hundred sixty-one million, sixty-five thousand, five hundred sixty-one".