19981707780 has 96 divisors (see below), whose sum is σ = 57388826880. Its totient is φ = 5192916480.

The previous prime is 19981707737. The next prime is 19981707799. The reversal of 19981707780 is 8770718991.

It is a self number, because there is not a number n which added to its sum of digits gives 19981707780.

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, 373897 + ... + 423983.

It is an arithmetic number, because the mean of its divisors is an integer number (597800280).

Almost surely, 2^19981707780 is an apocalyptic number.

19981707780 is a gapful number since it is divisible by the number (10) 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 19981707780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28694413440).

19981707780 is an abundant number, since it is smaller than the sum of its proper divisors (37407119100).

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

19981707780 is a wasteful number, since it uses less digits than its factorization.

19981707780 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 50269 (or 50267 counting only the distinct ones).

The product of its (nonzero) digits is 1778112, while the sum is 57.

The spelling of 19981707780 in words is "nineteen billion, nine hundred eighty-one million, seven hundred seven thousand, seven hundred eighty".