28919638885 has 4 divisors (see below), whose sum is σ = 34703566668. Its totient is φ = 23135711104.

The previous prime is 28919638871. The next prime is 28919638963. The reversal of 28919638885 is 58883691982.

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 8802755329 + 20116883556 = 93823^2 + 141834^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-28919638885 is a prime.

It is a Smith number, since the sum of its digits (67) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 28919638885.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2891963884 + ... + 2891963893.

It is an arithmetic number, because the mean of its divisors is an integer number (8675891667).

Almost surely, 2^28919638885 is an apocalyptic number.

It is an amenable number.

28919638885 is a deficient number, since it is larger than the sum of its proper divisors (5783927783).

28919638885 is an equidigital number, since it uses as much as digits as its factorization.

28919638885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5783927782.

The product of its digits is 59719680, while the sum is 67.

The spelling of 28919638885 in words is "twenty-eight billion, nine hundred nineteen million, six hundred thirty-eight thousand, eight hundred eighty-five".