161659728 has 60 divisors (see below), whose sum is σ = 453447540. Its totient is φ = 53764608.

The previous prime is 161659723. The next prime is 161659763. The reversal of 161659728 is 827956161.

161659728 is a `hidden beast` number, since 1 + 616 + 5 + 9 + 7 + 28 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 30603024 + 131056704 = 5532^2 + 11448^2 .

It is a super-3 number, since 3×161659728³ (a number of 26 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161659723) 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 11 ways as a sum of consecutive naturals, for example, 80950 + ... + 82922.

It is an arithmetic number, because the mean of its divisors is an integer number (7557459).

Almost surely, 2^161659728 is an apocalyptic number.

161659728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

161659728 is an abundant number, since it is smaller than the sum of its proper divisors (291787812).

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

161659728 is a wasteful number, since it uses less digits than its factorization.

161659728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2556 (or 2547 counting only the distinct ones).

The product of its digits is 181440, while the sum is 45.

The square root of 161659728 is about 12714.5478881477. The cubic root of 161659728 is about 544.7542342222.

The spelling of 161659728 in words is "one hundred sixty-one million, six hundred fifty-nine thousand, seven hundred twenty-eight".