28307857 has 8 divisors (see below), whose sum is σ = 29451240. Its totient is φ = 27175680.

The previous prime is 28307837. The next prime is 28307879. The reversal of 28307857 is 75870382.

It can be written as a sum of positive squares in 4 ways, for example, as 3297856 + 25010001 = 1816^2 + 5001^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28307857 is a prime.

It is not an unprimeable number, because it can be changed into a prime (28307827) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2553 + ... + 7945.

It is an arithmetic number, because the mean of its divisors is an integer number (3681405).

Almost surely, 2^28307857 is an apocalyptic number.

It is an amenable number.

28307857 is a deficient number, since it is larger than the sum of its proper divisors (1143383).

28307857 is a wasteful number, since it uses less digits than its factorization.

28307857 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5603.

The product of its (nonzero) digits is 94080, while the sum is 40.

The square root of 28307857 is about 5320.5128512203. The cubic root of 28307857 is about 304.7677421985.

The spelling of 28307857 in words is "twenty-eight million, three hundred seven thousand, eight hundred fifty-seven".