161071561728 has 528 divisors, whose sum is σ = 582400256256. Its totient is φ = 41653370880.

The previous prime is 161071561697. The next prime is 161071561751. The reversal of 161071561728 is 827165170161.

161071561728 is a `hidden beast` number, since 1 + 6 + 1 + 0 + 7 + 1 + 5 + 617 + 28 = 666.

It is a tau number, because it is divible by the number of its divisors (528).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 250499775 + ... + 250500417.

Almost surely, 2^161071561728 is an apocalyptic number.

161071561728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 161071561728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (291200128128).

161071561728 is an abundant number, since it is smaller than the sum of its proper divisors (421328694528).

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

161071561728 is a wasteful number, since it uses less digits than its factorization.

161071561728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1040 (or 1019 counting only the distinct ones).

The product of its (nonzero) digits is 141120, while the sum is 45.

The spelling of 161071561728 in words is "one hundred sixty-one billion, seventy-one million, five hundred sixty-one thousand, seven hundred twenty-eight".