865634400 has 216 divisors, whose sum is σ = 3083240160. Its totient is φ = 228510720.

The previous prime is 865634323. The next prime is 865634401. The reversal of 865634400 is 4436568.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (865634401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 784249 + ... + 785351.

It is an arithmetic number, because the mean of its divisors is an integer number (14274260).

Almost surely, 2^865634400 is an apocalyptic number.

865634400 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 865634400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1541620080).

865634400 is an abundant number, since it is smaller than the sum of its proper divisors (2217605760).

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

865634400 is a wasteful number, since it uses less digits than its factorization.

865634400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1238 (or 1222 counting only the distinct ones).

The product of its (nonzero) digits is 69120, while the sum is 36.

The square root of 865634400 is about 29421.6654865084. The cubic root of 865634400 is about 953.0408196190.

The spelling of 865634400 in words is "eight hundred sixty-five million, six hundred thirty-four thousand, four hundred".