20556809280 has 1008 divisors, whose sum is σ = 87885398016. Its totient is φ = 4389396480.

The previous prime is 20556809279. The next prime is 20556809303. The reversal of 20556809280 is 8290865502.

20556809280 is a `hidden beast` number, since 2 + 0 + 5 + 568 + 0 + 9 + 2 + 80 = 666.

It is a tau number, because it is divible by the number of its divisors (1008).

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

It is an unprimeable number.

It is a polite number, since it can be written in 143 ways as a sum of consecutive naturals, for example, 161864577 + ... + 161864703.

Almost surely, 2^20556809280 is an apocalyptic number.

20556809280 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 20556809280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43942699008).

20556809280 is an abundant number, since it is smaller than the sum of its proper divisors (67328588736).

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

20556809280 is a wasteful number, since it uses less digits than its factorization.

20556809280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 232 (or 212 counting only the distinct ones).

The product of its (nonzero) digits is 345600, while the sum is 45.

The spelling of 20556809280 in words is "twenty billion, five hundred fifty-six million, eight hundred nine thousand, two hundred eighty".