28891278 has 48 divisors (see below), whose sum is σ = 67800096. Its totient is φ = 8838720.

The previous prime is 28891273. The next prime is 28891309. The reversal of 28891278 is 87219882.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28891273) 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 23 ways as a sum of consecutive naturals, for example, 72576 + ... + 72972.

It is an arithmetic number, because the mean of its divisors is an integer number (1412502).

Almost surely, 2^28891278 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28891278, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33900048).

28891278 is an abundant number, since it is smaller than the sum of its proper divisors (38908818).

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

28891278 is a wasteful number, since it uses less digits than its factorization.

28891278 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 729 (or 726 counting only the distinct ones).

The product of its digits is 129024, while the sum is 45.

The square root of 28891278 is about 5375.0607438428. The cubic root of 28891278 is about 306.8472610404.

The spelling of 28891278 in words is "twenty-eight million, eight hundred ninety-one thousand, two hundred seventy-eight".