1161728161 has 4 divisors (see below), whose sum is σ = 1267339824. Its totient is φ = 1056116500.

The previous prime is 1161728143. The next prime is 1161728171. The reversal of 1161728161 is 1618271611.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 1161728161 - 2¹⁷ = 1161597089 is a prime.

It is a super-2 number, since 2×1161728161² = 2699224640120883842, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1161728111) 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 3 ways as a sum of consecutive naturals, for example, 52805815 + ... + 52805836.

It is an arithmetic number, because the mean of its divisors is an integer number (316834956).

Almost surely, 2^1161728161 is an apocalyptic number.

1161728161 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

1161728161 is a deficient number, since it is larger than the sum of its proper divisors (105611663).

1161728161 is a wasteful number, since it uses less digits than its factorization.

1161728161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 105611662.

The product of its digits is 4032, while the sum is 34.

The square root of 1161728161 is about 34084.1335668079. The cubic root of 1161728161 is about 1051.2390998298.

Adding to 1161728161 its reverse (1618271611), we get a palindrome (2779999772).

The spelling of 1161728161 in words is "one billion, one hundred sixty-one million, seven hundred twenty-eight thousand, one hundred sixty-one".