28878591 has 12 divisors (see below), whose sum is σ = 44791512. Its totient is φ = 16501968.

The previous prime is 28878571. The next prime is 28878601. The reversal of 28878591 is 19587882.

It is not a de Polignac number, because 28878591 - 2¹⁰ = 28877567 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 28878591.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28878571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 98080 + ... + 98373.

It is an arithmetic number, because the mean of its divisors is an integer number (3732626).

Almost surely, 2^28878591 is an apocalyptic number.

28878591 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

28878591 is a deficient number, since it is larger than the sum of its proper divisors (15912921).

28878591 is a wasteful number, since it uses less digits than its factorization.

28878591 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 196470 (or 196463 counting only the distinct ones).

The product of its digits is 322560, while the sum is 48.

The square root of 28878591 is about 5373.8804415431. The cubic root of 28878591 is about 306.8023392803.

The spelling of 28878591 in words is "twenty-eight million, eight hundred seventy-eight thousand, five hundred ninety-one".