161166061106561 has 12 divisors (see below), whose sum is σ = 187482961325700. Its totient is φ = 138139336258560.

The previous prime is 161166061106549. The next prime is 161166061106581. The reversal of 161166061106561 is 165601160661161.

It can be written as a sum of positive squares in 2 ways, for example, as 777615330625 + 160388445775936 = 881825^2 + 12664456^2 .

It is not a de Polignac number, because 161166061106561 - 2²² = 161166056912257 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161166061106581) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 33456680 + ... + 37969481.

It is an arithmetic number, because the mean of its divisors is an integer number (15623580110475).

Almost surely, 2^{161166061106561} is an apocalyptic number.

It is an amenable number.

161166061106561 is a deficient number, since it is larger than the sum of its proper divisors (26316900219139).

161166061106561 is an equidigital number, since it uses as much as digits as its factorization.

161166061106561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 71472224 (or 71472217 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 47.

The spelling of 161166061106561 in words is "one hundred sixty-one trillion, one hundred sixty-six billion, sixty-one million, one hundred six thousand, five hundred sixty-one".