161531340636 has 24 divisors (see below), whose sum is σ = 386099303184. Its totient is φ = 52530517120.

The previous prime is 161531340631. The next prime is 161531340637. The reversal of 161531340636 is 636043135161.

It is a junction number, because it is equal to n+sod(n) for n = 161531340594 and 161531340603.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161531340631) 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, 164157375 + ... + 164158358.

It is an arithmetic number, because the mean of its divisors is an integer number (16087470966).

Almost surely, 2^161531340636 is an apocalyptic number.

It is an amenable number.

161531340636 is an abundant number, since it is smaller than the sum of its proper divisors (224567962548).

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

161531340636 is a wasteful number, since it uses less digits than its factorization.

161531340636 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328315781 (or 328315779 counting only the distinct ones).

The product of its (nonzero) digits is 116640, while the sum is 39.

Adding to 161531340636 its reverse (636043135161), we get a palindrome (797574475797).

The spelling of 161531340636 in words is "one hundred sixty-one billion, five hundred thirty-one million, three hundred forty thousand, six hundred thirty-six".