161313886321 has 27 divisors (see below), whose sum is σ = 189290445057. Its totient is φ = 137071357920.

The previous prime is 161313886297. The next prime is 161313886367. The reversal of 161313886321 is 123688313161.

The square root of 161313886321 is 401639.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 142963391025 + 18350495296 = 378105^2 + 135464^2 .

It is not a de Polignac number, because 161313886321 - 2⁹ = 161313885809 is a prime.

It is not an unprimeable number, because it can be changed into a prime (161313886381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 26 ways as a sum of consecutive naturals, for example, 508876455 + ... + 508876771.

Almost surely, 2^161313886321 is an apocalyptic number.

161313886321 is the 401639-th square number.

161313886321 is the 200820-th centered octagonal number.

It is an amenable number.

161313886321 is a deficient number, since it is larger than the sum of its proper divisors (27976558736).

161313886321 is an frugal number, since it uses more digits than its factorization.

161313886321 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1010 (or 505 counting only the distinct ones).

The product of its digits is 124416, while the sum is 43.

The spelling of 161313886321 in words is "one hundred sixty-one billion, three hundred thirteen million, eight hundred eighty-six thousand, three hundred twenty-one".