161606111556561 has 16 divisors (see below), whose sum is σ = 248695119343488. Its totient is φ = 91432029168000.

The previous prime is 161606111556511. The next prime is 161606111556587. The reversal of 161606111556561 is 165655111606161.

It is not a de Polignac number, because 161606111556561 - 2¹⁴ = 161606111540177 is a prime.

It is a super-2 number, since 2×161606111556561² (a number of 29 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (161606111556511) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38096676700 + ... + 38096680941.

It is an arithmetic number, because the mean of its divisors is an integer number (15543444958968).

Almost surely, 2^{161606111556561} is an apocalyptic number.

It is an amenable number.

161606111556561 is a deficient number, since it is larger than the sum of its proper divisors (87089007786927).

161606111556561 is a wasteful number, since it uses less digits than its factorization.

161606111556561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76193357752.

The product of its (nonzero) digits is 972000, while the sum is 51.

The spelling of 161606111556561 in words is "one hundred sixty-one trillion, six hundred six billion, one hundred eleven million, five hundred fifty-six thousand, five hundred sixty-one".