9999729663840 has 1152 divisors, whose sum is σ = 41883762106368. Its totient is φ = 2204731146240.

The previous prime is 9999729663817. The next prime is 9999729663941. The reversal of 9999729663840 is 483669279999.

9999729663840 is a `hidden beast` number, since 9 + 99 + 97 + 2 + 9 + 66 + 384 + 0 = 666.

It is a super-3 number, since 3×9999729663840³ (a number of 40 digits) contains 333 as substring.

It is a Harshad number since it is a multiple of its sum of digits (81).

It is a self number, because there is not a number n which added to its sum of digits gives 9999729663840.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 2843253762 + ... + 2843257278.

It is an arithmetic number, because the mean of its divisors is an integer number (36357432384).

Almost surely, 2^{9999729663840} is an apocalyptic number.

9999729663840 is a gapful number since it is divisible by the number (90) 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 9999729663840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20941881053184).

9999729663840 is an abundant number, since it is smaller than the sum of its proper divisors (31884032442528).

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

9999729663840 is a wasteful number, since it uses less digits than its factorization.

9999729663840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3922 (or 3902 counting only the distinct ones).

The product of its (nonzero) digits is 2857026816, while the sum is 81.

The spelling of 9999729663840 in words is "nine trillion, nine hundred ninety-nine billion, seven hundred twenty-nine million, six hundred sixty-three thousand, eight hundred forty".