9666819940801 has 9 divisors (see below), whose sum is σ = 9708182386851. Its totient is φ = 9625633017504.

The previous prime is 9666819940781. The next prime is 9666819940807. The reversal of 9666819940801 is 1080499186669.

The square root of 9666819940801 is 3109151.

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

9666819940801 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 1927518499201 + 7739301441600 = 1388351^2 + 2781960^2 .

It is not a de Polignac number, because 9666819940801 - 2¹¹ = 9666819938753 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (9666819940807) by changing a digit.

It is a polite number, since it can be written in 8 ways as a sum of consecutive naturals, for example, 743080585 + ... + 743093593.

Almost surely, 2^{9666819940801} is an apocalyptic number.

9666819940801 is the 3109151-st square number.

9666819940801 is the 1554576-th centered octagonal number.

It is an amenable number.

9666819940801 is a deficient number, since it is larger than the sum of its proper divisors (41362446050).

9666819940801 is an frugal number, since it uses more digits than its factorization.

9666819940801 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26496 (or 13248 counting only the distinct ones).

The product of its (nonzero) digits is 40310784, while the sum is 67.

The spelling of 9666819940801 in words is "nine trillion, six hundred sixty-six billion, eight hundred nineteen million, nine hundred forty thousand, eight hundred one".