19998980 has 48 divisors (see below), whose sum is σ = 44558640. Its totient is φ = 7535360.

The previous prime is 19998977. The next prime is 19998989. The reversal of 19998980 is 8989991.

It can be written as a sum of positive squares in 8 ways, for example, as 8479744 + 11519236 = 2912^2 + 3394^2 .

It is not an unprimeable number, because it can be changed into a prime (19998989) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 487760 + ... + 487800.

It is an arithmetic number, because the mean of its divisors is an integer number (928305).

Almost surely, 2^19998980 is an apocalyptic number.

19998980 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 19998980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22279320).

19998980 is an abundant number, since it is smaller than the sum of its proper divisors (24559660).

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

19998980 is an equidigital number, since it uses as much as digits as its factorization.

19998980 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 137 (or 77 counting only the distinct ones).

The product of its (nonzero) digits is 419904, while the sum is 53.

The square root of 19998980 is about 4472.0219140787. The cubic root of 19998980 is about 271.4371470711.

The spelling of 19998980 in words is "nineteen million, nine hundred ninety-eight thousand, nine hundred eighty".