28840931 has 4 divisors (see below), whose sum is σ = 32961072. Its totient is φ = 24720792.

The previous prime is 28840921. The next prime is 28840937. The reversal of 28840931 is 13904882.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 13904882 = 2 ⋅6952441.

It is a cyclic number.

It is not a de Polignac number, because 28840931 - 2¹⁸ = 28578787 is a prime.

It is a super-3 number, since 3×28840931³ (a number of 23 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 28840891 and 28840900.

It is not an unprimeable number, because it can be changed into a prime (28840937) 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 3 ways as a sum of consecutive naturals, for example, 2060060 + ... + 2060073.

It is an arithmetic number, because the mean of its divisors is an integer number (8240268).

Almost surely, 2^28840931 is an apocalyptic number.

28840931 is a deficient number, since it is larger than the sum of its proper divisors (4120141).

28840931 is an equidigital number, since it uses as much as digits as its factorization.

28840931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4120140.

The product of its (nonzero) digits is 13824, while the sum is 35.

The square root of 28840931 is about 5370.3753127691. The cubic root of 28840931 is about 306.6689163088.

The spelling of 28840931 in words is "twenty-eight million, eight hundred forty thousand, nine hundred thirty-one".