28231289 has 2 divisors, whose sum is σ = 28231290. Its totient is φ = 28231288.

The previous prime is 28231277. The next prime is 28231387. The reversal of 28231289 is 98213282.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 27741289 + 490000 = 5267^2 + 700^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28231289 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (28231219) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14115644 + 14115645.

It is an arithmetic number, because the mean of its divisors is an integer number (14115645).

Almost surely, 2^28231289 is an apocalyptic number.

It is an amenable number.

28231289 is a deficient number, since it is larger than the sum of its proper divisors (1).

28231289 is an equidigital number, since it uses as much as digits as its factorization.

28231289 is an odious number, because the sum of its binary digits is odd.

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

The square root of 28231289 is about 5313.3124319957. The cubic root of 28231289 is about 304.4927122230.

The spelling of 28231289 in words is "twenty-eight million, two hundred thirty-one thousand, two hundred eighty-nine".