28832781 has 4 divisors (see below), whose sum is σ = 38443712. Its totient is φ = 19221852.

The previous prime is 28832779. The next prime is 28832801. The reversal of 28832781 is 18723882.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 28832781 - 2¹ = 28832779 is a prime.

It is a super-2 number, since 2×28832781² = 1662658520387922, 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 (28832711) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4805461 + ... + 4805466.

It is an arithmetic number, because the mean of its divisors is an integer number (9610928).

Almost surely, 2^28832781 is an apocalyptic number.

It is an amenable number.

28832781 is a deficient number, since it is larger than the sum of its proper divisors (9610931).

28832781 is an equidigital number, since it uses as much as digits as its factorization.

28832781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9610930.

The product of its digits is 43008, while the sum is 39.

The square root of 28832781 is about 5369.6164667507. The cubic root of 28832781 is about 306.6400269602.

The spelling of 28832781 in words is "twenty-eight million, eight hundred thirty-two thousand, seven hundred eighty-one".