28181238 has 8 divisors (see below), whose sum is σ = 56362488. Its totient is φ = 9393744.

The previous prime is 28181203. The next prime is 28181287. The reversal of 28181238 is 83218182.

It is a sphenic number, since it is the product of 3 distinct primes.

28181238 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 28181199 and 28181208.

It is a congruent number.

It is an unprimeable number.

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, 2348431 + ... + 2348442.

It is an arithmetic number, because the mean of its divisors is an integer number (7045311).

Almost surely, 2^28181238 is an apocalyptic number.

28181238 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28181238 is a wasteful number, since it uses less digits than its factorization.

28181238 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4696878.

The product of its digits is 6144, while the sum is 33.

The square root of 28181238 is about 5308.6003805146. The cubic root of 28181238 is about 304.3126616415.

The spelling of 28181238 in words is "twenty-eight million, one hundred eighty-one thousand, two hundred thirty-eight".