28343881 has 4 divisors (see below), whose sum is σ = 28766992. Its totient is φ = 27920772.

The previous prime is 28343873. The next prime is 28343891. The reversal of 28343881 is 18834382.

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 a cyclic number.

It is not a de Polignac number, because 28343881 - 2³ = 28343873 is a prime.

It is a super-2 number, since 2×28343881² = 1606751180284322, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28343881.

It is not an unprimeable number, because it can be changed into a prime (28343831) 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 3 ways as a sum of consecutive naturals, for example, 211455 + ... + 211588.

It is an arithmetic number, because the mean of its divisors is an integer number (7191748).

Almost surely, 2^28343881 is an apocalyptic number.

It is an amenable number.

28343881 is a deficient number, since it is larger than the sum of its proper divisors (423111).

28343881 is an equidigital number, since it uses as much as digits as its factorization.

28343881 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423110.

The product of its digits is 36864, while the sum is 37.

The square root of 28343881 is about 5323.8971627934. The cubic root of 28343881 is about 304.8969677964.

The spelling of 28343881 in words is "twenty-eight million, three hundred forty-three thousand, eight hundred eighty-one".