28161 has 16 divisors (see below), whose sum is σ = 48000. Its totient is φ = 15984.

The previous prime is 28151. The next prime is 28163. The reversal of 28161 is 16182.

It is not a de Polignac number, because 28161 - 2⁶ = 28097 is a prime.

28161 is a lucky number.

It is a nialpdrome in base 13.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28163) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 115 + ... + 263.

It is an arithmetic number, because the mean of its divisors is an integer number (3000).

It is a Proth number, since it is equal to 55 ⋅ 2⁹ + 1 and 55 < 2⁹.

2²⁸¹⁶¹ is an apocalyptic number.

28161 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

28161 is a deficient number, since it is larger than the sum of its proper divisors (19839).

28161 is a wasteful number, since it uses less digits than its factorization.

28161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 165 (or 159 counting only the distinct ones).

The product of its digits is 96, while the sum is 18.

The square root of 28161 is about 167.8123952514. The cubic root of 28161 is about 30.4239798099.

The spelling of 28161 in words is "twenty-eight thousand, one hundred sixty-one".