20981180844 has 288 divisors, whose sum is σ = 62771304960. Its totient is φ = 6074611200.

The previous prime is 20981180821. The next prime is 20981180849. The reversal of 20981180844 is 44808118902.

It is a self number, because there is not a number n which added to its sum of digits gives 20981180844.

It is not an unprimeable number, because it can be changed into a prime (20981180849) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 67463449 + ... + 67463759.

It is an arithmetic number, because the mean of its divisors is an integer number (217955920).

Almost surely, 2^20981180844 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 20981180844, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31385652480).

20981180844 is an abundant number, since it is smaller than the sum of its proper divisors (41790124116).

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

20981180844 is a wasteful number, since it uses less digits than its factorization.

20981180844 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 643 (or 629 counting only the distinct ones).

The product of its (nonzero) digits is 147456, while the sum is 45.

The spelling of 20981180844 in words is "twenty billion, nine hundred eighty-one million, one hundred eighty thousand, eight hundred forty-four".