28128531578 has 16 divisors (see below), whose sum is σ = 48282739200. Its totient is φ = 12039485136.

The previous prime is 28128531533. The next prime is 28128531581. The reversal of 28128531578 is 87513582182.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1288778 + ... + 1310421.

It is an arithmetic number, because the mean of its divisors is an integer number (3017671200).

Almost surely, 2^28128531578 is an apocalyptic number.

28128531578 is a deficient number, since it is larger than the sum of its proper divisors (20154207622).

28128531578 is a wasteful number, since it uses less digits than its factorization.

28128531578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2599981.

The product of its digits is 1075200, while the sum is 50.

The spelling of 28128531578 in words is "twenty-eight billion, one hundred twenty-eight million, five hundred thirty-one thousand, five hundred seventy-eight".