28686281 has 8 divisors (see below), whose sum is σ = 30994824. Its totient is φ = 26392320.

The previous prime is 28686271. The next prime is 28686367. The reversal of 28686281 is 18268682.

It can be written as a sum of positive squares in 4 ways, for example, as 160000 + 28526281 = 400^2 + 5341^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 28686281 - 2¹⁴ = 28669897 is a prime.

It is a super-2 number, since 2×28686281² = 1645805435221922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28686271) 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, 641 + ... + 7601.

It is an arithmetic number, because the mean of its divisors is an integer number (3874353).

Almost surely, 2^28686281 is an apocalyptic number.

It is an amenable number.

28686281 is a deficient number, since it is larger than the sum of its proper divisors (2308543).

28686281 is a wasteful number, since it uses less digits than its factorization.

28686281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7291.

The product of its digits is 73728, while the sum is 41.

The square root of 28686281 is about 5355.9575241034. The cubic root of 28686281 is about 306.1197966019.

The spelling of 28686281 in words is "twenty-eight million, six hundred eighty-six thousand, two hundred eighty-one".