28921057256 has 128 divisors (see below), whose sum is σ = 69912460800. Its totient is φ = 10901468160.

The previous prime is 28921057247. The next prime is 28921057283. The reversal of 28921057256 is 65275012982.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 28921057256.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4500926 + ... + 4507346.

It is an arithmetic number, because the mean of its divisors is an integer number (546191100).

Almost surely, 2^28921057256 is an apocalyptic number.

28921057256 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 28921057256, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34956230400).

28921057256 is an abundant number, since it is smaller than the sum of its proper divisors (40991403544).

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

28921057256 is a wasteful number, since it uses less digits than its factorization.

28921057256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6739 (or 6735 counting only the distinct ones).

The product of its (nonzero) digits is 604800, while the sum is 47.

The spelling of 28921057256 in words is "twenty-eight billion, nine hundred twenty-one million, fifty-seven thousand, two hundred fifty-six".