28676781 has 16 divisors (see below), whose sum is σ = 48553600. Its totient is φ = 16386624.

The previous prime is 28676777. The next prime is 28676783. The reversal of 28676781 is 18767682.

It is not a de Polignac number, because 28676781 - 2² = 28676777 is a prime.

It is a super-2 number, since 2×28676781² = 1644715537043922, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28676783) 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, 75676 + ... + 76053.

It is an arithmetic number, because the mean of its divisors is an integer number (3034600).

Almost surely, 2^28676781 is an apocalyptic number.

28676781 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

28676781 is a deficient number, since it is larger than the sum of its proper divisors (19876819).

28676781 is a wasteful number, since it uses less digits than its factorization.

28676781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151745 (or 151739 counting only the distinct ones).

The product of its digits is 225792, while the sum is 45.

The square root of 28676781 is about 5355.0705877701. The cubic root of 28676781 is about 306.0860004335.

Subtracting from 28676781 its reverse (18767682), we obtain a palindrome (9909099).

The spelling of 28676781 in words is "twenty-eight million, six hundred seventy-six thousand, seven hundred eighty-one".