28776281 has 8 divisors (see below), whose sum is σ = 29220840. Its totient is φ = 28334592.

The previous prime is 28776239. The next prime is 28776283. The reversal of 28776281 is 18267782.

It can be written as a sum of positive squares in 4 ways, for example, as 855625 + 27920656 = 925^2 + 5284^2 .

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 28776281 - 2⁶ = 28776217 is a prime.

It is a super-2 number, since 2×28776281² = 1656148696381922, which contains 22 as substring.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28776283) 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, 27341 + ... + 28373.

It is an arithmetic number, because the mean of its divisors is an integer number (3652605).

Almost surely, 2^28776281 is an apocalyptic number.

It is an amenable number.

28776281 is a deficient number, since it is larger than the sum of its proper divisors (444559).

28776281 is a wasteful number, since it uses less digits than its factorization.

28776281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1435.

The product of its digits is 75264, while the sum is 41.

The square root of 28776281 is about 5364.3528034610. The cubic root of 28776281 is about 306.4396012652.

The spelling of 28776281 in words is "twenty-eight million, seven hundred seventy-six thousand, two hundred eighty-one".