28506878440 has 32 divisors (see below), whose sum is σ = 64245165480. Its totient is φ = 11384140032.

The previous prime is 28506878357. The next prime is 28506878441. The reversal of 28506878440 is 4487860582.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 11142491364 + 17364387076 = 105558^2 + 131774^2 .

It is a Smith number, since the sum of its digits (52) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (28506878441) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 556779 + ... + 605818.

Almost surely, 2^28506878440 is an apocalyptic number.

28506878440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

28506878440 is an abundant number, since it is smaller than the sum of its proper divisors (35738287040).

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

28506878440 is a wasteful number, since it uses less digits than its factorization.

28506878440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1163221 (or 1163217 counting only the distinct ones).

The product of its (nonzero) digits is 3440640, while the sum is 52.

The spelling of 28506878440 in words is "twenty-eight billion, five hundred six million, eight hundred seventy-eight thousand, four hundred forty".