28881784889 has 4 divisors (see below), whose sum is σ = 28882148724. Its totient is φ = 28881421056.

The previous prime is 28881784873. The next prime is 28881784909. The reversal of 28881784889 is 98848718882.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It can be written as a sum of positive squares in 2 ways, for example, as 7622686864 + 21259098025 = 87308^2 + 145805^2 .

It is a cyclic number.

It is not a de Polignac number, because 28881784889 - 2⁴ = 28881784873 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (28881784829) 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, 6392 + ... + 240425.

It is an arithmetic number, because the mean of its divisors is an integer number (7220537181).

Almost surely, 2^28881784889 is an apocalyptic number.

It is an amenable number.

28881784889 is a deficient number, since it is larger than the sum of its proper divisors (363835).

28881784889 is a wasteful number, since it uses less digits than its factorization.

28881784889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 363834.

The product of its digits is 132120576, while the sum is 71.

The spelling of 28881784889 in words is "twenty-eight billion, eight hundred eighty-one million, seven hundred eighty-four thousand, eight hundred eighty-nine".