28184381 has 4 divisors (see below), whose sum is σ = 28265952. Its totient is φ = 28102812.

The previous prime is 28184371. The next prime is 28184389. The reversal of 28184381 is 18348182.

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, and also an emirpimes, since its reverse is a distinct semiprime: 18348182 = 2 ⋅9174091.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28184381 is a prime.

It is a super-2 number, since 2×28184381² = 1588718664706322, 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 (28184389) 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, 40265 + ... + 40958.

It is an arithmetic number, because the mean of its divisors is an integer number (7066488).

Almost surely, 2^28184381 is an apocalyptic number.

It is an amenable number.

28184381 is a deficient number, since it is larger than the sum of its proper divisors (81571).

28184381 is an equidigital number, since it uses as much as digits as its factorization.

28184381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 81570.

The product of its digits is 12288, while the sum is 35.

The square root of 28184381 is about 5308.8964013249. The cubic root of 28184381 is about 304.3239743588.

The spelling of 28184381 in words is "twenty-eight million, one hundred eighty-four thousand, three hundred eighty-one".