28207881 has 12 divisors (see below), whose sum is σ = 43879108. Its totient is φ = 17358624.

The previous prime is 28207853. The next prime is 28207901. The reversal of 28207881 is 18870282.

It can be written as a sum of positive squares in 2 ways, for example, as 9363600 + 18844281 = 3060^2 + 4341^2 .

It is not a de Polignac number, because 28207881 - 2¹⁸ = 27945737 is a prime.

It is a super-3 number, since 3×28207881³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (28207181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 120430 + ... + 120663.

Almost surely, 2^28207881 is an apocalyptic number.

It is an amenable number.

28207881 is a deficient number, since it is larger than the sum of its proper divisors (15671227).

28207881 is a wasteful number, since it uses less digits than its factorization.

28207881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 241112 (or 241109 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 36.

The square root of 28207881 is about 5311.1092061828. The cubic root of 28207881 is about 304.4085321458.

It can be divided in two parts, 2820 and 7881, that added together give a palindrome (10701).

The spelling of 28207881 in words is "twenty-eight million, two hundred seven thousand, eight hundred eighty-one".