28820709 has 6 divisors (see below), whose sum is σ = 41629926. Its totient is φ = 19213800.

The previous prime is 28820699. The next prime is 28820713. The reversal of 28820709 is 90702882.

It can be written as a sum of positive squares in only one way, i.e., 28323684 + 497025 = 5322^2 + 705^2 .

It is not a de Polignac number, because 28820709 - 2⁸ = 28820453 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28820719) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1601142 + ... + 1601159.

It is an arithmetic number, because the mean of its divisors is an integer number (6938321).

Almost surely, 2^28820709 is an apocalyptic number.

It is an amenable number.

28820709 is a deficient number, since it is larger than the sum of its proper divisors (12809217).

28820709 is a wasteful number, since it uses less digits than its factorization.

28820709 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3202307 (or 3202304 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 36.

The square root of 28820709 is about 5368.4922464320. The cubic root of 28820709 is about 306.5972252715.

The spelling of 28820709 in words is "twenty-eight million, eight hundred twenty thousand, seven hundred nine".