28705921272 has 144 divisors (see below), whose sum is σ = 90835781400. Its totient is φ = 8165646720.

The previous prime is 28705921271. The next prime is 28705921303. The reversal of 28705921272 is 27212950782.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28705921271) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 790147 + ... + 825677.

Almost surely, 2^28705921272 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28705921272, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45417890700).

28705921272 is an abundant number, since it is smaller than the sum of its proper divisors (62129860128).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

28705921272 is a wasteful number, since it uses less digits than its factorization.

28705921272 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 35786 (or 35772 counting only the distinct ones).

The product of its (nonzero) digits is 282240, while the sum is 45.

The spelling of 28705921272 in words is "twenty-eight billion, seven hundred five million, nine hundred twenty-one thousand, two hundred seventy-two".