28281689857 has 8 divisors (see below), whose sum is σ = 28672059240. Its totient is φ = 27891400320.

The previous prime is 28281689837. The next prime is 28281689869. The reversal of 28281689857 is 75898618282.

It can be written as a sum of positive squares in 4 ways, for example, as 311134321 + 27970555536 = 17639^2 + 167244^2 .

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-28281689857 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28281689837) 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, 1217007 + ... + 1240027.

It is an arithmetic number, because the mean of its divisors is an integer number (3584007405).

Almost surely, 2^28281689857 is an apocalyptic number.

It is an amenable number.

28281689857 is a deficient number, since it is larger than the sum of its proper divisors (390369383).

28281689857 is a wasteful number, since it uses less digits than its factorization.

28281689857 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 39923.

The product of its digits is 30965760, while the sum is 64.

The spelling of 28281689857 in words is "twenty-eight billion, two hundred eighty-one million, six hundred eighty-nine thousand, eight hundred fifty-seven".