161606656511665 has 8 divisors (see below), whose sum is σ = 193984808223528. Its totient is φ = 129247444936320.

The previous prime is 161606656511653. The next prime is 161606656511813. The reversal of 161606656511665 is 566115656606161.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 109611351567936 + 51995304943729 = 10469544^2 + 7210777^2 .

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

It is not a de Polignac number, because 161606656511665 - 2²⁵ = 161606622957233 is a prime.

It is a super-2 number, since 2×161606656511665² (a number of 29 digits) contains 22 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4735015356 + ... + 4735049485.

It is an arithmetic number, because the mean of its divisors is an integer number (24248101027941).

Almost surely, 2^{161606656511665} is an apocalyptic number.

It is an amenable number.

161606656511665 is a deficient number, since it is larger than the sum of its proper divisors (32378151711863).

161606656511665 is an equidigital number, since it uses as much as digits as its factorization.

161606656511665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9470068259.

The product of its (nonzero) digits is 34992000, while the sum is 61.

The spelling of 161606656511665 in words is "one hundred sixty-one trillion, six hundred six billion, six hundred fifty-six million, five hundred eleven thousand, six hundred sixty-five".