9961756574721 has 32 divisors (see below), whose sum is σ = 15256977270528. Its totient is φ = 5663562854400.

The previous prime is 9961756574683. The next prime is 9961756574729. The reversal of 9961756574721 is 1274756571699.

It is not a de Polignac number, because 9961756574721 - 2⁶ = 9961756574657 is a prime.

It is not an unprimeable number, because it can be changed into a prime (9961756574729) by changing a digit.

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, 2351025 + ... + 5044881.

It is an arithmetic number, because the mean of its divisors is an integer number (476780539704).

Almost surely, 2^{9961756574721} is an apocalyptic number.

It is an amenable number.

9961756574721 is a deficient number, since it is larger than the sum of its proper divisors (5295220695807).

9961756574721 is a wasteful number, since it uses less digits than its factorization.

9961756574721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2694761.

The product of its digits is 200037600, while the sum is 69.

The spelling of 9961756574721 in words is "nine trillion, nine hundred sixty-one billion, seven hundred fifty-six million, five hundred seventy-four thousand, seven hundred twenty-one".