28688772578 has 4 divisors (see below), whose sum is σ = 43033158870. Its totient is φ = 14344386288.

The previous prime is 28688772523. The next prime is 28688772583. The reversal of 28688772578 is 87527788682.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 87527788682 = 2 ⋅43763894341.

It can be written as a sum of positive squares in only one way, i.e., 20558684689 + 8130087889 = 143383^2 + 90167^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7172193143 + ... + 7172193146.

Almost surely, 2^28688772578 is an apocalyptic number.

28688772578 is a deficient number, since it is larger than the sum of its proper divisors (14344386292).

28688772578 is a wasteful number, since it uses less digits than its factorization.

28688772578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14344386291.

The product of its digits is 168591360, while the sum is 68.

The spelling of 28688772578 in words is "twenty-eight billion, six hundred eighty-eight million, seven hundred seventy-two thousand, five hundred seventy-eight".