28971726555589 has 4 divisors (see below), whose sum is σ = 29970751609260. Its totient is φ = 27972701501920.

The previous prime is 28971726555523. The next prime is 28971726555661. The reversal of 28971726555589 is 98555562717982.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 10418531450625 + 18553195104964 = 3227775^2 + 4307342^2 .

It is a cyclic number.

It is not a de Polignac number, because 28971726555589 - 2⁹ = 28971726555077 is a prime.

It is a super-2 number, since 2×28971726555589² (a number of 28 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28971726055589) 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, 499512526792 + ... + 499512526849.

It is an arithmetic number, because the mean of its divisors is an integer number (7492687902315).

Almost surely, 2^{28971726555589} is an apocalyptic number.

28971726555589 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

28971726555589 is a deficient number, since it is larger than the sum of its proper divisors (999025053671).

28971726555589 is an equidigital number, since it uses as much as digits as its factorization.

28971726555589 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 999025053670.

The product of its digits is 3810240000, while the sum is 79.

The spelling of 28971726555589 in words is "twenty-eight trillion, nine hundred seventy-one billion, seven hundred twenty-six million, five hundred fifty-five thousand, five hundred eighty-nine".