28673281 has 12 divisors (see below), whose sum is σ = 35921172. Its totient is φ = 22686048.

The previous prime is 28673269. The next prime is 28673311. The reversal of 28673281 is 18237682.

It can be written as a sum of positive squares in 2 ways, for example, as 2202256 + 26471025 = 1484^2 + 5145^2 .

It is not a de Polignac number, because 28673281 - 2¹⁷ = 28542209 is a prime.

It is a super-2 number, since 2×28673281² = 1644314086609922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 28673281.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28673201) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 21870 + ... + 23143.

It is an arithmetic number, because the mean of its divisors is an integer number (2993431).

Almost surely, 2^28673281 is an apocalyptic number.

It is an amenable number.

28673281 is a deficient number, since it is larger than the sum of its proper divisors (7247891).

28673281 is a wasteful number, since it uses less digits than its factorization.

28673281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 45040 (or 45033 counting only the distinct ones).

The product of its digits is 32256, while the sum is 37.

The square root of 28673281 is about 5354.7437847202. The cubic root of 28673281 is about 306.0735473320.

The spelling of 28673281 in words is "twenty-eight million, six hundred seventy-three thousand, two hundred eighty-one".