861386400 has 504 divisors, whose sum is σ = 3620330784. Its totient is φ = 195955200.

The previous prime is 861386399. The next prime is 861386441. The reversal of 861386400 is 4683168.

It is a happy number.

861386400 is a `hidden beast` number, since 8 + 6 + 1 + 3 + 8 + 640 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (504).

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 83 ways as a sum of consecutive naturals, for example, 4082295 + ... + 4082505.

It is an arithmetic number, because the mean of its divisors is an integer number (7183196).

Almost surely, 2^861386400 is an apocalyptic number.

861386400 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 861386400, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1810165392).

861386400 is an abundant number, since it is smaller than the sum of its proper divisors (2758944384).

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

861386400 is a wasteful number, since it uses less digits than its factorization.

861386400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256 (or 228 counting only the distinct ones).

The product of its (nonzero) digits is 27648, while the sum is 36.

The square root of 861386400 is about 29349.3850020746. The cubic root of 861386400 is about 951.4792835330.

The spelling of 861386400 in words is "eight hundred sixty-one million, three hundred eighty-six thousand, four hundred".