20961047808 has 288 divisors, whose sum is σ = 64964860800. Its totient is φ = 6740858880.

The previous prime is 20961047759. The next prime is 20961047839. The reversal of 20961047808 is 80874016902.

20961047808 is a `hidden beast` number, since 20 + 9 + 610 + 4 + 7 + 8 + 0 + 8 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 16235643 + ... + 16236933.

Almost surely, 2^20961047808 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20961047808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32482430400).

20961047808 is an abundant number, since it is smaller than the sum of its proper divisors (44003812992).

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

20961047808 is an frugal number, since it uses more digits than its factorization.

20961047808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1357 (or 1325 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 45.

The spelling of 20961047808 in words is "twenty billion, nine hundred sixty-one million, forty-seven thousand, eight hundred eight".