9964685442721 has 9 divisors (see below), whose sum is σ = 10130914671033. Its totient is φ = 9801140542320.

The previous prime is 9964685442713. The next prime is 9964685442763. The reversal of 9964685442721 is 1272445864699.

The square root of 9964685442721 is 3156689.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in 4 ways, for example, as 1498447740321 + 8466237702400 = 1224111^2 + 2909680^2 .

It is not a de Polignac number, because 9964685442721 - 2³ = 9964685442713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9964685442421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 192532155 + ... + 192583903.

Almost surely, 2^{9964685442721} is an apocalyptic number.

9964685442721 is the 3156689-th square number.

9964685442721 is the 1578345-th centered octagonal number.

It is an amenable number.

9964685442721 is a deficient number, since it is larger than the sum of its proper divisors (166229228312).

9964685442721 is an frugal number, since it uses more digits than its factorization.

9964685442721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 103620 (or 51810 counting only the distinct ones).

The product of its digits is 209018880, while the sum is 67.

The spelling of 9964685442721 in words is "nine trillion, nine hundred sixty-four billion, six hundred eighty-five million, four hundred forty-two thousand, seven hundred twenty-one".