865121568 has 96 divisors (see below), whose sum is σ = 2469688704. Its totient is φ = 264056832.

The previous prime is 865121567. The next prime is 865121599.

865121568 is nontrivially palindromic in base 10.

It is a tau number, because it is divible by the number of its divisors (96).

It is not an unprimeable number, because it can be changed into a prime (865121567) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 53221 + ... + 67547.

It is an arithmetic number, because the mean of its divisors is an integer number (25725924).

Almost surely, 2^865121568 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 865121568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1234844352).

865121568 is an abundant number, since it is smaller than the sum of its proper divisors (1604567136).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

865121568 is a wasteful number, since it uses less digits than its factorization.

865121568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14394 (or 14386 counting only the distinct ones).

The product of its digits is 115200, while the sum is 42.

The square root of 865121568 is about 29412.9489850984. The cubic root of 865121568 is about 952.8525775702.

The spelling of 865121568 in words is "eight hundred sixty-five million, one hundred twenty-one thousand, five hundred sixty-eight".