161941728 has 144 divisors (see below), whose sum is σ = 487393200. Its totient is φ = 46792704.

The previous prime is 161941723. The next prime is 161941729. The reversal of 161941728 is 827149161.

It is a Harshad number since it is a multiple of its sum of digits (39).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161941723) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 360448 + ... + 360896.

It is an arithmetic number, because the mean of its divisors is an integer number (3384675).

Almost surely, 2^161941728 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 161941728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (243696600).

161941728 is an abundant number, since it is smaller than the sum of its proper divisors (325451472).

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

161941728 is a wasteful number, since it uses less digits than its factorization.

161941728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 509 (or 484 counting only the distinct ones).

The product of its digits is 24192, while the sum is 39.

The square root of 161941728 is about 12725.6327151148. The cubic root of 161941728 is about 545.0708075103.

The spelling of 161941728 in words is "one hundred sixty-one million, nine hundred forty-one thousand, seven hundred twenty-eight".