865712120 has 128 divisors (see below), whose sum is σ = 2453552640. Its totient is φ = 267563520.

The previous prime is 865712119. The next prime is 865712149. The reversal of 865712120 is 21217568.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 153755 + ... + 159285.

It is an arithmetic number, because the mean of its divisors is an integer number (19168380).

Almost surely, 2^865712120 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 865712120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1226776320).

865712120 is an abundant number, since it is smaller than the sum of its proper divisors (1587840520).

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

865712120 is a wasteful number, since it uses less digits than its factorization.

865712120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5605 (or 5601 counting only the distinct ones).

The product of its (nonzero) digits is 6720, while the sum is 32.

The square root of 865712120 is about 29422.9862522484. The cubic root of 865712120 is about 953.0693413274.

Adding to 865712120 its reverse (21217568), we get a palindrome (886929688).

The spelling of 865712120 in words is "eight hundred sixty-five million, seven hundred twelve thousand, one hundred twenty".