161606506566138 has 32 divisors (see below), whose sum is σ = 324723224168640. Its totient is φ = 53617514764800.

The previous prime is 161606506566083. The next prime is 161606506566139. The reversal of 161606506566138 is 831665605606161.

It is a super-2 number, since 2×161606506566138² (a number of 29 digits) contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (161606506566139) 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, 45938295 + ... + 49330922.

It is an arithmetic number, because the mean of its divisors is an integer number (10147600755270).

Almost surely, 2^{161606506566138} is an apocalyptic number.

161606506566138 is an abundant number, since it is smaller than the sum of its proper divisors (163116717602502).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

161606506566138 is a wasteful number, since it uses less digits than its factorization.

161606506566138 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 95270542.

The product of its (nonzero) digits is 27993600, while the sum is 60.

The spelling of 161606506566138 in words is "one hundred sixty-one trillion, six hundred six billion, five hundred six million, five hundred sixty-six thousand, one hundred thirty-eight".