28187173728 has 144 divisors (see below), whose sum is σ = 92515995936. Its totient is φ = 7973683200.

The previous prime is 28187173717. The next prime is 28187173733. The reversal of 28187173728 is 82737178182.

It is a tau number, because it is divible by the number of its divisors (144).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 134400 + ... + 272832.

It is an arithmetic number, because the mean of its divisors is an integer number (642472194).

Almost surely, 2^28187173728 is an apocalyptic number.

28187173728 is a gapful number since it is divisible by the number (28) 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 28187173728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (46257997968).

28187173728 is an abundant number, since it is smaller than the sum of its proper divisors (64328822208).

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

28187173728 is a wasteful number, since it uses less digits than its factorization.

28187173728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 138557 (or 138546 counting only the distinct ones).

The product of its digits is 2107392, while the sum is 54.

The spelling of 28187173728 in words is "twenty-eight billion, one hundred eighty-seven million, one hundred seventy-three thousand, seven hundred twenty-eight".