161497728 has 144 divisors (see below), whose sum is σ = 540789210. Its totient is φ = 46126080.

The previous prime is 161497727. The next prime is 161497741. The reversal of 161497728 is 827794161.

It is a happy number.

161497728 is a `hidden beast` number, since 1 + 614 + 9 + 7 + 7 + 28 = 666.

It can be written as a sum of positive squares in only one way, i.e., 134374464 + 27123264 = 11592^2 + 5208^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is a super-2 number, since 2×161497728² = 52163032298323968, which contains 22 as substring.

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (161497727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 55018 + ... + 57878.

Almost surely, 2^161497728 is an apocalyptic number.

161497728 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 161497728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (270394605).

161497728 is an abundant number, since it is smaller than the sum of its proper divisors (379291482).

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

161497728 is a wasteful number, since it uses less digits than its factorization.

161497728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2895 (or 2873 counting only the distinct ones).

The product of its digits is 169344, while the sum is 45.

The square root of 161497728 is about 12708.1756361800. The cubic root of 161497728 is about 544.5722064487.

The spelling of 161497728 in words is "one hundred sixty-one million, four hundred ninety-seven thousand, seven hundred twenty-eight".