28871309 has 2 divisors, whose sum is σ = 28871310. Its totient is φ = 28871308.

The previous prime is 28871303. The next prime is 28871329. The reversal of 28871309 is 90317882.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28590409 + 280900 = 5347^2 + 530^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28871309 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (28871303) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 14435654 + 14435655.

It is an arithmetic number, because the mean of its divisors is an integer number (14435655).

Almost surely, 2^28871309 is an apocalyptic number.

It is an amenable number.

28871309 is a deficient number, since it is larger than the sum of its proper divisors (1).

28871309 is an equidigital number, since it uses as much as digits as its factorization.

28871309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 24192, while the sum is 38.

The square root of 28871309 is about 5373.2028623531. The cubic root of 28871309 is about 306.7765494435.

The spelling of 28871309 in words is "twenty-eight million, eight hundred seventy-one thousand, three hundred nine".