861288400 has 120 divisors (see below), whose sum is σ = 2446629120. Its totient is φ = 285089280.

The previous prime is 861288397. The next prime is 861288403. The reversal of 861288400 is 4882168.

It is an interprime number because it is at equal distance from previous prime (861288397) and next prime (861288403).

It is a self number, because there is not a number n which added to its sum of digits gives 861288400.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (861288403) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 75897 + ... + 86503.

It is an arithmetic number, because the mean of its divisors is an integer number (20388576).

Almost surely, 2^861288400 is an apocalyptic number.

861288400 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 861288400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1223314560).

861288400 is an abundant number, since it is smaller than the sum of its proper divisors (1585340720).

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

861288400 is a wasteful number, since it uses less digits than its factorization.

861288400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10661 (or 10650 counting only the distinct ones).

The product of its (nonzero) digits is 24576, while the sum is 37.

The square root of 861288400 is about 29347.7154136400. The cubic root of 861288400 is about 951.4431988730.

The spelling of 861288400 in words is "eight hundred sixty-one million, two hundred eighty-eight thousand, four hundred".