28289881 has 2 divisors, whose sum is σ = 28289882. Its totient is φ = 28289880.

The previous prime is 28289873. The next prime is 28289897. The reversal of 28289881 is 18898282.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 25918281 + 2371600 = 5091^2 + 1540^2 .

It is a cyclic number.

It is not a de Polignac number, because 28289881 - 2³ = 28289873 is a prime.

It is a super-2 number, since 2×28289881² = 1600634733988322, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28289801) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14144940 + 14144941.

It is an arithmetic number, because the mean of its divisors is an integer number (14144941).

Almost surely, 2^28289881 is an apocalyptic number.

It is an amenable number.

28289881 is a deficient number, since it is larger than the sum of its proper divisors (1).

28289881 is an equidigital number, since it uses as much as digits as its factorization.

28289881 is an evil number, because the sum of its binary digits is even.

The product of its digits is 147456, while the sum is 46.

The square root of 28289881 is about 5318.8232721157. The cubic root of 28289881 is about 304.7032175333.

The spelling of 28289881 in words is "twenty-eight million, two hundred eighty-nine thousand, eight hundred eighty-one".