28181243 has 4 divisors (see below), whose sum is σ = 29153040. Its totient is φ = 27209448.

The previous prime is 28181203. The next prime is 28181287. The reversal of 28181243 is 34218182.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 28181243 - 2¹⁰ = 28180219 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (29), and also a Moran number because the ratio is a prime number: 971767 = 28181243 / (2 + 8 + 1 + 8 + 1 + 2 + 4 + 3).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28181203) 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, 485855 + ... + 485912.

It is an arithmetic number, because the mean of its divisors is an integer number (7288260).

Almost surely, 2^28181243 is an apocalyptic number.

28181243 is a deficient number, since it is larger than the sum of its proper divisors (971797).

28181243 is an equidigital number, since it uses as much as digits as its factorization.

28181243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 971796.

The product of its digits is 3072, while the sum is 29.

The square root of 28181243 is about 5308.6008514485. The cubic root of 28181243 is about 304.3126796388.

The spelling of 28181243 in words is "twenty-eight million, one hundred eighty-one thousand, two hundred forty-three".