19887736665888 has 576 divisors, whose sum is σ = 71912403763200. Its totient is φ = 5071686359040.

The previous prime is 19887736665833. The next prime is 19887736665893. The reversal of 19887736665888 is 88856663778891.

It is a junction number, because it is equal to n+sod(n) for n = 19887736665798 and 19887736665807.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1039111423 + ... + 1039130561.

It is an arithmetic number, because the mean of its divisors is an integer number (124847923200).

Almost surely, 2^{19887736665888} is an apocalyptic number.

19887736665888 is a gapful number since it is divisible by the number (18) 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 19887736665888, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35956201881600).

19887736665888 is an abundant number, since it is smaller than the sum of its proper divisors (52024667097312).

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

19887736665888 is a wasteful number, since it uses less digits than its factorization.

19887736665888 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20485 (or 20474 counting only the distinct ones).

The product of its digits is 46820229120, while the sum is 90.

The spelling of 19887736665888 in words is "nineteen trillion, eight hundred eighty-seven billion, seven hundred thirty-six million, six hundred sixty-five thousand, eight hundred eighty-eight".