28121838 has 8 divisors (see below), whose sum is σ = 56243688. Its totient is φ = 9373944.

The previous prime is 28121827. The next prime is 28121857. The reversal of 28121838 is 83812182.

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

28121838 is an admirable number.

It is a junction number, because it is equal to n+sod(n) for n = 28121799 and 28121808.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2343481 + ... + 2343492.

It is an arithmetic number, because the mean of its divisors is an integer number (7030461).

Almost surely, 2^28121838 is an apocalyptic number.

28121838 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.

28121838 is a wasteful number, since it uses less digits than its factorization.

28121838 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4686978.

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

The square root of 28121838 is about 5303.0027343006. The cubic root of 28121838 is about 304.0987026566.

The spelling of 28121838 in words is "twenty-eight million, one hundred twenty-one thousand, eight hundred thirty-eight".