28255532778 has 80 divisors (see below), whose sum is σ = 69104629440. Its totient is φ = 8557876800.

The previous prime is 28255532761. The next prime is 28255532779. The reversal of 28255532778 is 87723555282.

28255532778 is a `hidden beast` number, since 2 + 82 + 5 + 553 + 2 + 7 + 7 + 8 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (28255532779) 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 39 ways as a sum of consecutive naturals, for example, 5683878 + ... + 5688846.

It is an arithmetic number, because the mean of its divisors is an integer number (863807868).

Almost surely, 2^28255532778 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28255532778, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34552314720).

28255532778 is an abundant number, since it is smaller than the sum of its proper divisors (40849096662).

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

28255532778 is a wasteful number, since it uses less digits than its factorization.

28255532778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8185 (or 8176 counting only the distinct ones).

The product of its digits is 9408000, while the sum is 54.

The spelling of 28255532778 in words is "twenty-eight billion, two hundred fifty-five million, five hundred thirty-two thousand, seven hundred seventy-eight".