28812881 has 16 divisors (see below), whose sum is σ = 30554304. Its totient is φ = 27143424.

The previous prime is 28812877. The next prime is 28812907. The reversal of 28812881 is 18821882.

It is a cyclic number.

It is not a de Polignac number, because 28812881 - 2² = 28812877 is a prime.

It is a super-2 number, since 2×28812881² = 1660364223040322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28812821) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 210245 + ... + 210381.

It is an arithmetic number, because the mean of its divisors is an integer number (1909644).

Almost surely, 2^28812881 is an apocalyptic number.

It is an amenable number.

28812881 is a deficient number, since it is larger than the sum of its proper divisors (1741423).

28812881 is a wasteful number, since it uses less digits than its factorization.

28812881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 320.

The product of its digits is 16384, while the sum is 38.

The square root of 28812881 is about 5367.7631281568. The cubic root of 28812881 is about 306.5694644415.

Subtracting from 28812881 its reverse (18821882), we obtain a palindrome (9990999).

The spelling of 28812881 in words is "twenty-eight million, eight hundred twelve thousand, eight hundred eighty-one".