9865166721 has 8 divisors (see below), whose sum is σ = 13158382944. Its totient is φ = 6574364160.

The previous prime is 9865166671. The next prime is 9865166741. The reversal of 9865166721 is 1276615689.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 9865166721 - 2⁷ = 9865166593 is a prime.

It is not an unprimeable number, because it can be changed into a prime (9865166741) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 593856 + ... + 610241.

It is an arithmetic number, because the mean of its divisors is an integer number (1644797868).

Almost surely, 2^9865166721 is an apocalyptic number.

It is an amenable number.

9865166721 is a deficient number, since it is larger than the sum of its proper divisors (3293216223).

9865166721 is a wasteful number, since it uses less digits than its factorization.

9865166721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1206831.

The product of its digits is 1088640, while the sum is 51.

The square root of 9865166721 is about 99323.5456525793. The cubic root of 9865166721 is about 2144.7078583445.

The spelling of 9865166721 in words is "nine billion, eight hundred sixty-five million, one hundred sixty-six thousand, seven hundred twenty-one".