20891566080 has 912 divisors, whose sum is σ = 94220665344. Its totient is φ = 4152360960.

The previous prime is 20891566079. The next prime is 20891566093. The reversal of 20891566080 is 8066519802.

20891566080 is a `hidden beast` number, since 2 + 0 + 8 + 9 + 1 + 566 + 0 + 80 = 666.

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

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 47 ways as a sum of consecutive naturals, for example, 908328949 + ... + 908328971.

Almost surely, 2^20891566080 is an apocalyptic number.

20891566080 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 20891566080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47110332672).

20891566080 is an abundant number, since it is smaller than the sum of its proper divisors (73329099264).

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

20891566080 is an equidigital number, since it uses as much as digits as its factorization.

20891566080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88 (or 51 counting only the distinct ones).

The product of its (nonzero) digits is 207360, while the sum is 45.

The spelling of 20891566080 in words is "twenty billion, eight hundred ninety-one million, five hundred sixty-six thousand, eighty".