20928784091904 has 288 divisors, whose sum is σ = 66799444824000. Its totient is φ = 6425271336960.

The previous prime is 20928784091791. The next prime is 20928784091947. The reversal of 20928784091904 is 40919048782902.

20928784091904 is a `hidden beast` number, since 209 + 2 + 8 + 7 + 8 + 409 + 19 + 0 + 4 = 666.

It is a tau number, because it is divible by the number of its divisors (288).

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, 40085974 + ... + 40604714.

It is an arithmetic number, because the mean of its divisors is an integer number (231942516750).

Almost surely, 2^{20928784091904} is an apocalyptic number.

20928784091904 is a gapful number since it is divisible by the number (24) 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 20928784091904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33399722412000).

20928784091904 is an abundant number, since it is smaller than the sum of its proper divisors (45870660732096).

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

20928784091904 is a wasteful number, since it uses less digits than its factorization.

20928784091904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 519228 (or 519208 counting only the distinct ones).

The product of its (nonzero) digits is 20901888, while the sum is 63.

The spelling of 20928784091904 in words is "twenty trillion, nine hundred twenty-eight billion, seven hundred eighty-four million, ninety-one thousand, nine hundred four".