28718891520 has 320 divisors, whose sum is σ = 106054033536. Its totient is φ = 6552289280.

The previous prime is 28718891479. The next prime is 28718891527. The reversal of 28718891520 is 2519881782.

It is a tau number, because it is divible by the number of its divisors (320).

It is a Harshad number since it is a multiple of its sum of digits (51).

It is not an unprimeable number, because it can be changed into a prime (28718891527) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1426162 + ... + 1446158.

Almost surely, 2^28718891520 is an apocalyptic number.

28718891520 is a gapful number since it is divisible by the number (20) 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 28718891520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (53027016768).

28718891520 is an abundant number, since it is smaller than the sum of its proper divisors (77335142016).

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

28718891520 is a wasteful number, since it uses less digits than its factorization.

28718891520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20051 (or 20035 counting only the distinct ones).

The product of its (nonzero) digits is 645120, while the sum is 51.

The spelling of 28718891520 in words is "twenty-eight billion, seven hundred eighteen million, eight hundred ninety-one thousand, five hundred twenty".