28778878 has 4 divisors (see below), whose sum is σ = 43168320. Its totient is φ = 14389438.

The previous prime is 28778861. The next prime is 28778879. The reversal of 28778878 is 87887782.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28778879) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7194718 + ... + 7194721.

It is an arithmetic number, because the mean of its divisors is an integer number (10792080).

Almost surely, 2^28778878 is an apocalyptic number.

28778878 is a deficient number, since it is larger than the sum of its proper divisors (14389442).

28778878 is a wasteful number, since it uses less digits than its factorization.

28778878 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14389441.

The product of its digits is 2809856, while the sum is 55.

The square root of 28778878 is about 5364.5948588873. The cubic root of 28778878 is about 306.4488195019.

The spelling of 28778878 in words is "twenty-eight million, seven hundred seventy-eight thousand, eight hundred seventy-eight".