9981656518656 has 104 divisors (see below), whose sum is σ = 26667429526080. Its totient is φ = 3320602034176.

The previous prime is 9981656518609. The next prime is 9981656518657. The reversal of 9981656518656 is 6568156561899.

It is a super-3 number, since 3×9981656518656³ (a number of 40 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (9981656518657) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5373400 + ... + 6988328.

Almost surely, 2^{9981656518656} is an apocalyptic number.

9981656518656 is a gapful number since it is divisible by the number (96) 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 9981656518656, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (13333714763040).

9981656518656 is an abundant number, since it is smaller than the sum of its proper divisors (16685773007424).

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

9981656518656 is a wasteful number, since it uses less digits than its factorization.

9981656518656 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1615459 (or 1615437 counting only the distinct ones).

The product of its digits is 839808000, while the sum is 75.

The spelling of 9981656518656 in words is "nine trillion, nine hundred eighty-one billion, six hundred fifty-six million, five hundred eighteen thousand, six hundred fifty-six".