865821600 has 432 divisors, whose sum is σ = 3582895680. Its totient is φ = 192614400.

The previous prime is 865821547. The next prime is 865821631. The reversal of 865821600 is 6128568.

It is a happy number.

865821600 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

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

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 2066191 + ... + 2066609.

It is an arithmetic number, because the mean of its divisors is an integer number (8293740).

Almost surely, 2^865821600 is an apocalyptic number.

865821600 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 865821600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1791447840).

865821600 is an abundant number, since it is smaller than the sum of its proper divisors (2717074080).

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

865821600 is a wasteful number, since it uses less digits than its factorization.

865821600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 493 (or 477 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The square root of 865821600 is about 29424.8466436106. The cubic root of 865821600 is about 953.1095154342.

The spelling of 865821600 in words is "eight hundred sixty-five million, eight hundred twenty-one thousand, six hundred".