161555010601 has 4 divisors (see below), whose sum is σ = 163768093012. Its totient is φ = 159341928192.

The previous prime is 161555010599. The next prime is 161555010629. The reversal of 161555010601 is 106010555161.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 94556865001 + 66998145600 = 307501^2 + 258840^2 .

It is a cyclic number.

It is not a de Polignac number, because 161555010601 - 2¹ = 161555010599 is a prime.

It is a super-2 number, since 2×161555010601² (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 (161556010601) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1106541096 + ... + 1106541241.

It is an arithmetic number, because the mean of its divisors is an integer number (40942023253).

Almost surely, 2^161555010601 is an apocalyptic number.

It is an amenable number.

161555010601 is a deficient number, since it is larger than the sum of its proper divisors (2213082411).

161555010601 is an equidigital number, since it uses as much as digits as its factorization.

161555010601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2213082410.

The product of its (nonzero) digits is 4500, while the sum is 31.

Adding to 161555010601 its reverse (106010555161), we get a palindrome (267565565762).

The spelling of 161555010601 in words is "one hundred sixty-one billion, five hundred fifty-five million, ten thousand, six hundred one".