865203121 has 8 divisors (see below), whose sum is σ = 909932544. Its totient is φ = 821066400.

The previous prime is 865203109. The next prime is 865203161. The reversal of 865203121 is 121302568.

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

It is a cyclic number.

It is not a de Polignac number, because 865203121 - 2¹³ = 865194929 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 865203121.

It is not an unprimeable number, because it can be changed into a prime (865203161) 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 7 ways as a sum of consecutive naturals, for example, 145180 + ... + 151021.

It is an arithmetic number, because the mean of its divisors is an integer number (113741568).

Almost surely, 2^865203121 is an apocalyptic number.

It is an amenable number.

865203121 is a deficient number, since it is larger than the sum of its proper divisors (44729423).

865203121 is a wasteful number, since it uses less digits than its factorization.

865203121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 296351.

The product of its (nonzero) digits is 2880, while the sum is 28.

The square root of 865203121 is about 29414.3352976062. The cubic root of 865203121 is about 952.8825176956.

Adding to 865203121 its reverse (121302568), we get a palindrome (986505689).

The spelling of 865203121 in words is "eight hundred sixty-five million, two hundred three thousand, one hundred twenty-one".