161661612313 has 8 divisors (see below), whose sum is σ = 161793569160. Its totient is φ = 161529713280.

The previous prime is 161661612283. The next prime is 161661612341. The reversal of 161661612313 is 313216166161.

It can be written as a sum of positive squares in 4 ways, for example, as 57843617049 + 103817995264 = 240507^2 + 322208^2 .

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 161661612313 - 2⁹ = 161661611801 is a prime.

It is a super-2 number, since 2×161661612313² (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 (161661612373) 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 7 ways as a sum of consecutive naturals, for example, 6835653 + ... + 6859261.

It is an arithmetic number, because the mean of its divisors is an integer number (20224196145).

Almost surely, 2^161661612313 is an apocalyptic number.

It is an amenable number.

161661612313 is a deficient number, since it is larger than the sum of its proper divisors (131956847).

161661612313 is a wasteful number, since it uses less digits than its factorization.

161661612313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28907.

The product of its digits is 23328, while the sum is 37.

Adding to 161661612313 its reverse (313216166161), we get a palindrome (474877778474).

The spelling of 161661612313 in words is "one hundred sixty-one billion, six hundred sixty-one million, six hundred twelve thousand, three hundred thirteen".