28289231 has 2 divisors, whose sum is σ = 28289232. Its totient is φ = 28289230.

The previous prime is 28289167. The next prime is 28289237. The reversal of 28289231 is 13298282.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 28289231 - 2⁶ = 28289167 is a prime.

It is a super-2 number, since 2×28289231² = 1600561181142722, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 28289191 and 28289200.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28289237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14144615 + 14144616.

It is an arithmetic number, because the mean of its divisors is an integer number (14144616).

Almost surely, 2^28289231 is an apocalyptic number.

28289231 is a deficient number, since it is larger than the sum of its proper divisors (1).

28289231 is an equidigital number, since it uses as much as digits as its factorization.

28289231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13824, while the sum is 35.

The square root of 28289231 is about 5318.7621680237. The cubic root of 28289231 is about 304.7008838530.

The spelling of 28289231 in words is "twenty-eight million, two hundred eighty-nine thousand, two hundred thirty-one".