161556005 has 8 divisors (see below), whose sum is σ = 208780152. Its totient is φ = 119302848.

The previous prime is 161556001. The next prime is 161556007. The reversal of 161556005 is 500655161.

It can be written as a sum of positive squares in 4 ways, for example, as 27019204 + 134536801 = 5198^2 + 11599^2 .

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 161556005 - 2² = 161556001 is a prime.

It is a super-2 number, since 2×161556005² = 52200685503120050, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161556001) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1242674 + ... + 1242803.

It is an arithmetic number, because the mean of its divisors is an integer number (26097519).

Almost surely, 2^161556005 is an apocalyptic number.

It is an amenable number.

161556005 is a deficient number, since it is larger than the sum of its proper divisors (47224147).

161556005 is a wasteful number, since it uses less digits than its factorization.

161556005 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2485495.

The product of its (nonzero) digits is 4500, while the sum is 29.

The square root of 161556005 is about 12710.4683233939. The cubic root of 161556005 is about 544.6377021439.

The spelling of 161556005 in words is "one hundred sixty-one million, five hundred fifty-six thousand, five".