28712857 has 6 divisors (see below), whose sum is σ = 30303978. Its totient is φ = 27201312.

The previous prime is 28712843. The next prime is 28712869. The reversal of 28712857 is 75821782.

It can be written as a sum of positive squares in only one way, i.e., 28504921 + 207936 = 5339^2 + 456^2 .

It is not a de Polignac number, because 28712857 - 2¹⁹ = 28188569 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28712807) 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, 39408 + ... + 40129.

It is an arithmetic number, because the mean of its divisors is an integer number (5050663).

Almost surely, 2^28712857 is an apocalyptic number.

It is an amenable number.

28712857 is a deficient number, since it is larger than the sum of its proper divisors (1591121).

28712857 is an equidigital number, since it uses as much as digits as its factorization.

28712857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 79575 (or 79556 counting only the distinct ones).

The product of its digits is 62720, while the sum is 40.

The square root of 28712857 is about 5358.4379253659. The cubic root of 28712857 is about 306.2143008783.

The spelling of 28712857 in words is "twenty-eight million, seven hundred twelve thousand, eight hundred fifty-seven".