28161289 has 8 divisors (see below), whose sum is σ = 30449160. Its totient is φ = 25890816.

The previous prime is 28161277. The next prime is 28161313. The reversal of 28161289 is 98216182.

It can be written as a sum of positive squares in 4 ways, for example, as 3211264 + 24950025 = 1792^2 + 4995^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 28161289 - 2⁵ = 28161257 is a prime.

It is a super-3 number, since 3×28161289³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28161229) 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 7 ways as a sum of consecutive naturals, for example, 874 + ... + 7555.

It is an arithmetic number, because the mean of its divisors is an integer number (3806145).

Almost surely, 2^28161289 is an apocalyptic number.

It is an amenable number.

28161289 is a deficient number, since it is larger than the sum of its proper divisors (2287871).

28161289 is a wasteful number, since it uses less digits than its factorization.

28161289 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8699.

The product of its digits is 13824, while the sum is 37.

The square root of 28161289 is about 5306.7211157173. The cubic root of 28161289 is about 304.2408388410.

The spelling of 28161289 in words is "twenty-eight million, one hundred sixty-one thousand, two hundred eighty-nine".