161728394 has 4 divisors (see below), whose sum is σ = 242592594. Its totient is φ = 80864196.

The previous prime is 161728393. The next prime is 161728417. The reversal of 161728394 is 493827161.

161728394 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 493827161 = 701 ⋅704461.

It can be written as a sum of positive squares in only one way, i.e., 159087769 + 2640625 = 12613^2 + 1625^2 .

It is not an unprimeable number, because it can be changed into a prime (161728393) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 40432097 + ... + 40432100.

Almost surely, 2^161728394 is an apocalyptic number.

161728394 is a deficient number, since it is larger than the sum of its proper divisors (80864200).

161728394 is an equidigital number, since it uses as much as digits as its factorization.

161728394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80864199.

The product of its digits is 72576, while the sum is 41.

The square root of 161728394 is about 12717.2478941004. The cubic root of 161728394 is about 544.8313525822.

The spelling of 161728394 in words is "one hundred sixty-one million, seven hundred twenty-eight thousand, three hundred ninety-four".