20818917280 has 192 divisors, whose sum is σ = 58825751040. Its totient is φ = 6813241344.

The previous prime is 20818917257. The next prime is 20818917299. The reversal of 20818917280 is 8271981802.

It is a super-2 number, since 2×20818917280² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20818917280.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2191581 + ... + 2201059.

It is an arithmetic number, because the mean of its divisors is an integer number (306384120).

Almost surely, 2^20818917280 is an apocalyptic number.

20818917280 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 20818917280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29412875520).

20818917280 is an abundant number, since it is smaller than the sum of its proper divisors (38006833760).

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

20818917280 is a wasteful number, since it uses less digits than its factorization.

20818917280 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9591 (or 9583 counting only the distinct ones).

The product of its (nonzero) digits is 129024, while the sum is 46.

The spelling of 20818917280 in words is "twenty billion, eight hundred eighteen million, nine hundred seventeen thousand, two hundred eighty".