28516561920 has 1760 divisors, whose sum is σ = 136961003520. Its totient is φ = 5494210560.

The previous prime is 28516561877. The next prime is 28516561921. The reversal of 28516561920 is 2916561582.

28516561920 is a `hidden beast` number, since 2 + 8 + 5 + 1 + 6 + 5 + 619 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (1760).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28516561921) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 606735337 + ... + 606735383.

It is an arithmetic number, because the mean of its divisors is an integer number (77818752).

Almost surely, 2^28516561920 is an apocalyptic number.

28516561920 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 28516561920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (68480501760).

28516561920 is an abundant number, since it is smaller than the sum of its proper divisors (108444441600).

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

28516561920 is a wasteful number, since it uses less digits than its factorization.

28516561920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 121 (or 94 counting only the distinct ones).

The product of its (nonzero) digits is 259200, while the sum is 45.

The spelling of 28516561920 in words is "twenty-eight billion, five hundred sixteen million, five hundred sixty-one thousand, nine hundred twenty".