9961981212672 has 384 divisors, whose sum is σ = 30143969856000. Its totient is φ = 3249998069760.

The previous prime is 9961981212661. The next prime is 9961981212683. The reversal of 9961981212672 is 2762121891699.

9961981212672 is a `hidden beast` number, since 9 + 9 + 619 + 8 + 1 + 2 + 1 + 2 + 6 + 7 + 2 = 666.

It is an interprime number because it is at equal distance from previous prime (9961981212661) and next prime (9961981212683).

It is a tau number, because it is divible by the number of its divisors (384).

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 31 ways as a sum of consecutive naturals, for example, 528786229 + ... + 528805067.

It is an arithmetic number, because the mean of its divisors is an integer number (78499921500).

Almost surely, 2^{9961981212672} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 9961981212672, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (15071984928000).

9961981212672 is an abundant number, since it is smaller than the sum of its proper divisors (20181988643328).

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

9961981212672 is a wasteful number, since it uses less digits than its factorization.

9961981212672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19074 (or 19048 counting only the distinct ones).

The product of its digits is 11757312, while the sum is 63.

The spelling of 9961981212672 in words is "nine trillion, nine hundred sixty-one billion, nine hundred eighty-one million, two hundred twelve thousand, six hundred seventy-two".