861600 has 72 divisors (see below), whose sum is σ = 2812320. Its totient is φ = 229120.

The previous prime is 861599. The next prime is 861613. The reversal of 861600 is 6168.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 861600.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2221 + ... + 2579.

It is an arithmetic number, because the mean of its divisors is an integer number (39060).

2⁸⁶¹⁶⁰⁰ is an apocalyptic number.

861600 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 861600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1406160).

861600 is an abundant number, since it is smaller than the sum of its proper divisors (1950720).

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

861600 is a wasteful number, since it uses less digits than its factorization.

861600 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 382 (or 369 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 21.

The square root of 861600 is about 928.2241108698. The cubic root of 861600 is about 95.1557923881.

Adding to 861600 its reverse (6168), we get a palindrome (867768).

The spelling of 861600 in words is "eight hundred sixty-one thousand, six hundred".