28981121 has 8 divisors (see below), whose sum is σ = 32287080. Its totient is φ = 25828992.

The previous prime is 28981111. The next prime is 28981129. The reversal of 28981121 is 12118982.

It can be written as a sum of positive squares in 4 ways, for example, as 8151025 + 20830096 = 2855^2 + 4564^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 28981121 - 2¹⁰ = 28980097 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28981129) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 38060 + ... + 38813.

It is an arithmetic number, because the mean of its divisors is an integer number (4035885).

Almost surely, 2^28981121 is an apocalyptic number.

It is an amenable number.

28981121 is a deficient number, since it is larger than the sum of its proper divisors (3305959).

28981121 is a wasteful number, since it uses less digits than its factorization.

28981121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 76915.

The product of its digits is 2304, while the sum is 32.

The square root of 28981121 is about 5383.4116506171. The cubic root of 28981121 is about 307.1649988210.

The spelling of 28981121 in words is "twenty-eight million, nine hundred eighty-one thousand, one hundred twenty-one".