28986281 has 4 divisors (see below), whose sum is σ = 29769732. Its totient is φ = 28202832.

The previous prime is 28986253. The next prime is 28986301. The reversal of 28986281 is 18268982.

28986281 = 589² + 590² + ... + 662².

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 16736281 + 12250000 = 4091^2 + 3500^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28986281 is a prime.

It is a super-2 number, since 2×28986281² = 1680408972421922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28986211) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 391670 + ... + 391743.

It is an arithmetic number, because the mean of its divisors is an integer number (7442433).

Almost surely, 2^28986281 is an apocalyptic number.

It is an amenable number.

28986281 is a deficient number, since it is larger than the sum of its proper divisors (783451).

28986281 is an equidigital number, since it uses as much as digits as its factorization.

28986281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 783450.

The product of its digits is 110592, while the sum is 44.

The square root of 28986281 is about 5383.8908792805. The cubic root of 28986281 is about 307.1832276689.

The spelling of 28986281 in words is "twenty-eight million, nine hundred eighty-six thousand, two hundred eighty-one".