861404544 has 640 divisors, whose sum is σ = 3483406080. Its totient is φ = 204042240.

The previous prime is 861404519. The next prime is 861404591. The reversal of 861404544 is 445404168.

It is a happy number.

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

It is a junction number, because it is equal to n+sod(n) for n = 861404499 and 861404508.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 10378327 + ... + 10378409.

It is an arithmetic number, because the mean of its divisors is an integer number (5442822).

Almost surely, 2^861404544 is an apocalyptic number.

861404544 is a gapful number since it is divisible by the number (84) 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 861404544, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1741703040).

861404544 is an abundant number, since it is smaller than the sum of its proper divisors (2622001536).

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

861404544 is a wasteful number, since it uses less digits than its factorization.

861404544 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 140 (or 119 counting only the distinct ones).

The product of its (nonzero) digits is 61440, while the sum is 36.

The square root of 861404544 is about 29349.6941040277. The cubic root of 861404544 is about 951.4859640498.

The spelling of 861404544 in words is "eight hundred sixty-one million, four hundred four thousand, five hundred forty-four".