28382281 has 4 divisors (see below), whose sum is σ = 28393092. Its totient is φ = 28371472.

The previous prime is 28382273. The next prime is 28382311. The reversal of 28382281 is 18228382.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 24010000 + 4372281 = 4900^2 + 2091^2 .

It is a cyclic number.

It is not a de Polignac number, because 28382281 - 2³ = 28382273 is a prime.

It is a super-2 number, since 2×28382281² = 1611107749525922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28382581) 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, 1335 + ... + 7651.

It is an arithmetic number, because the mean of its divisors is an integer number (7098273).

Almost surely, 2^28382281 is an apocalyptic number.

It is an amenable number.

28382281 is a deficient number, since it is larger than the sum of its proper divisors (10811).

28382281 is an equidigital number, since it uses as much as digits as its factorization.

28382281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10810.

The product of its digits is 12288, while the sum is 34.

The square root of 28382281 is about 5327.5023228526. The cubic root of 28382281 is about 305.0345960935.

The spelling of 28382281 in words is "twenty-eight million, three hundred eighty-two thousand, two hundred eighty-one".