28989431687 has 4 divisors (see below), whose sum is σ = 28990065720. Its totient is φ = 28988797656.

The previous prime is 28989431671. The next prime is 28989431689. The reversal of 28989431687 is 78613498982.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 28989431687 - 2⁴ = 28989431671 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28989431689) 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, 242612 + ... + 341817.

It is an arithmetic number, because the mean of its divisors is an integer number (7247516430).

Almost surely, 2^28989431687 is an apocalyptic number.

28989431687 is a deficient number, since it is larger than the sum of its proper divisors (634033).

28989431687 is an equidigital number, since it uses as much as digits as its factorization.

28989431687 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 634032.

The product of its digits is 41803776, while the sum is 65.

The spelling of 28989431687 in words is "twenty-eight billion, nine hundred eighty-nine million, four hundred thirty-one thousand, six hundred eighty-seven".