9661845939201 has 9 divisors (see below), whose sum is σ = 13956013159491. Its totient is φ = 6441224409432.

The previous prime is 9661845939133. The next prime is 9661845939223. The reversal of 9661845939201 is 1029395481669.

The square root of 9661845939201 is 3108351.

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

9661845939201 is a `hidden beast` number, since 9 + 6 + 6 + 18 + 4 + 593 + 9 + 20 + 1 = 666.

It can be written as a sum of positive squares in only one way, i.e., 9368649680625 + 293196258576 = 3060825^2 + 541476^2 .

It is a tau number, because it is divible by the number of its divisors (9).

It is not a de Polignac number, because 9661845939201 - 2²⁵ = 9661812384769 is a prime.

It is not an unprimeable number, because it can be changed into a prime (9661845939281) 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, 8806995 + ... + 9843111.

Almost surely, 2^{9661845939201} is an apocalyptic number.

9661845939201 is the 3108351-st square number.

9661845939201 is the 1554176-th centered octagonal number.

It is an amenable number.

9661845939201 is a deficient number, since it is larger than the sum of its proper divisors (4294167220290).

9661845939201 is an frugal number, since it uses more digits than its factorization.

9661845939201 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2072240 (or 1036120 counting only the distinct ones).

The product of its (nonzero) digits is 25194240, while the sum is 63.

The spelling of 9661845939201 in words is "nine trillion, six hundred sixty-one billion, eight hundred forty-five million, nine hundred thirty-nine thousand, two hundred one".