161661147218 has 16 divisors (see below), whose sum is σ = 244936151640. Its totient is φ = 80016048000.

The previous prime is 161661147217. The next prime is 161661147239. The reversal of 161661147218 is 812741166161.

It can be written as a sum of positive squares in 4 ways, for example, as 160226480089 + 1434667129 = 400283^2 + 37877^2 .

It is a super-3 number, since 3×161661147218³ (a number of 35 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is not an unprimeable number, because it can be changed into a prime (161661147211) 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, 1117358 + ... + 1253718.

Almost surely, 2^161661147218 is an apocalyptic number.

161661147218 is a deficient number, since it is larger than the sum of its proper divisors (83275004422).

161661147218 is a wasteful number, since it uses less digits than its factorization.

161661147218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 142333.

The product of its digits is 96768, while the sum is 44.

The spelling of 161661147218 in words is "one hundred sixty-one billion, six hundred sixty-one million, one hundred forty-seven thousand, two hundred eighteen".