28971378889 has 4 divisors (see below), whose sum is σ = 29118441924. Its totient is φ = 28824315856.

The previous prime is 28971378883. The next prime is 28971378893. The reversal of 28971378889 is 98887317982.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 98887317982 = 2 ⋅49443658991.

It can be written as a sum of positive squares in 2 ways, for example, as 14474014864 + 14497364025 = 120308^2 + 120405^2 .

It is a cyclic number.

It is not a de Polignac number, because 28971378889 - 2¹⁵ = 28971346121 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28971378883) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 73531222 + ... + 73531615.

It is an arithmetic number, because the mean of its divisors is an integer number (7279610481).

Almost surely, 2^28971378889 is an apocalyptic number.

It is an amenable number.

28971378889 is a deficient number, since it is larger than the sum of its proper divisors (147063035).

28971378889 is a wasteful number, since it uses less digits than its factorization.

28971378889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147063034.

The product of its digits is 97542144, while the sum is 70.

The spelling of 28971378889 in words is "twenty-eight billion, nine hundred seventy-one million, three hundred seventy-eight thousand, eight hundred eighty-nine".