161000555561 has 8 divisors (see below), whose sum is σ = 162562331904. Its totient is φ = 159445895040.

The previous prime is 161000555549. The next prime is 161000555567. The reversal of 161000555561 is 165555000161.

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 161000555561 - 2¹⁴ = 161000539177 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161000555567) 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, 1733480 + ... + 1823993.

It is an arithmetic number, because the mean of its divisors is an integer number (20320291488).

Almost surely, 2^161000555561 is an apocalyptic number.

It is an amenable number.

161000555561 is a deficient number, since it is larger than the sum of its proper divisors (1561776343).

161000555561 is a wasteful number, since it uses less digits than its factorization.

161000555561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3557911.

The product of its (nonzero) digits is 22500, while the sum is 35.

The spelling of 161000555561 in words is "one hundred sixty-one billion, five hundred fifty-five thousand, five hundred sixty-one".