161556332809 has 16 divisors (see below), whose sum is σ = 170784345600. Its totient is φ = 152513577216.

The previous prime is 161556332807. The next prime is 161556332813. The reversal of 161556332809 is 908233655161.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 161556332809 - 2¹ = 161556332807 is a prime.

It is a super-2 number, since 2×161556332809² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161556332807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4767277 + ... + 4801045.

It is an arithmetic number, because the mean of its divisors is an integer number (10674021600).

Almost surely, 2^161556332809 is an apocalyptic number.

It is an amenable number.

161556332809 is a deficient number, since it is larger than the sum of its proper divisors (9228012791).

161556332809 is a wasteful number, since it uses less digits than its factorization.

161556332809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36504.

The product of its (nonzero) digits is 1166400, while the sum is 49.

The spelling of 161556332809 in words is "one hundred sixty-one billion, five hundred fifty-six million, three hundred thirty-two thousand, eight hundred nine".