161631909504 has 192 divisors, whose sum is σ = 501647546400. Its totient is φ = 49657743360.

The previous prime is 161631909503. The next prime is 161631909539. The reversal of 161631909504 is 405909136161.

161631909504 is a `hidden beast` number, since 1 + 6 + 1 + 631 + 9 + 0 + 9 + 5 + 0 + 4 = 666.

161631909504 is digitally balanced in base 7, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (192).

It is a super-2 number, since 2×161631909504² (a number of 23 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 161631909504.

It is not an unprimeable number, because it can be changed into a prime (161631909503) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 10340607 + ... + 10356225.

Almost surely, 2^161631909504 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161631909504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (250823773200).

161631909504 is an abundant number, since it is smaller than the sum of its proper divisors (340015636896).

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

161631909504 is a wasteful number, since it uses less digits than its factorization.

161631909504 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16343 (or 16328 counting only the distinct ones).

The product of its (nonzero) digits is 174960, while the sum is 45.

The spelling of 161631909504 in words is "one hundred sixty-one billion, six hundred thirty-one million, nine hundred nine thousand, five hundred four".