19981533600 has 1440 divisors, whose sum is σ = 90744192000. Its totient is φ = 4267468800.

The previous prime is 19981533581. The next prime is 19981533617. The reversal of 19981533600 is 633518991.

19981533600 is a `hidden beast` number, since 1 + 9 + 9 + 8 + 1 + 5 + 33 + 600 = 666.

It is a tau number, because it is divible by the number of its divisors (1440).

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

It is an unprimeable number.

It is a polite number, since it can be written in 239 ways as a sum of consecutive naturals, for example, 644565585 + ... + 644565615.

It is an arithmetic number, because the mean of its divisors is an integer number (63016800).

Almost surely, 2^19981533600 is an apocalyptic number.

19981533600 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 19981533600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45372096000).

19981533600 is an abundant number, since it is smaller than the sum of its proper divisors (70762658400).

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

19981533600 is a wasteful number, since it uses less digits than its factorization.

19981533600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 113 (or 77 counting only the distinct ones).

The product of its (nonzero) digits is 174960, while the sum is 45.

The spelling of 19981533600 in words is "nineteen billion, nine hundred eighty-one million, five hundred thirty-three thousand, six hundred".