19987916400 has 720 divisors, whose sum is σ = 77236723200. Its totient is φ = 4949268480.

The previous prime is 19987916387. The next prime is 19987916453. The reversal of 19987916400 is 461978991.

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

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 143 ways as a sum of consecutive naturals, for example, 145897132 + ... + 145897268.

Almost surely, 2^19987916400 is an apocalyptic number.

19987916400 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 19987916400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38618361600).

19987916400 is an abundant number, since it is smaller than the sum of its proper divisors (57248806800).

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

19987916400 is a wasteful number, since it uses less digits than its factorization.

19987916400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 268 (or 245 counting only the distinct ones).

The product of its (nonzero) digits is 979776, while the sum is 54.

The spelling of 19987916400 in words is "nineteen billion, nine hundred eighty-seven million, nine hundred sixteen thousand, four hundred".