161640442313 has 12 divisors (see below), whose sum is σ = 188039468052. Its totient is φ = 138542503680.

The previous prime is 161640442307. The next prime is 161640442339. The reversal of 161640442313 is 313244046161.

It can be written as a sum of positive squares in 2 ways, for example, as 14604239104 + 147036203209 = 120848^2 + 383453^2 .

It is not a de Polignac number, because 161640442313 - 2⁴ = 161640442297 is a prime.

It is a super-2 number, since 2×161640442313² (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 (161640442303) 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 11 ways as a sum of consecutive naturals, for example, 1202381 + ... + 1330037.

It is an arithmetic number, because the mean of its divisors is an integer number (15669955671).

Almost surely, 2^161640442313 is an apocalyptic number.

It is an amenable number.

161640442313 is a deficient number, since it is larger than the sum of its proper divisors (26399025739).

161640442313 is a wasteful number, since it uses less digits than its factorization.

161640442313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153512 (or 153505 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 35.

Adding to 161640442313 its reverse (313244046161), we get a palindrome (474884488474).

The spelling of 161640442313 in words is "one hundred sixty-one billion, six hundred forty million, four hundred forty-two thousand, three hundred thirteen".