861404544000 has 3520 divisors, whose sum is σ = 4362207962112. Its totient is φ = 163233792000.

The previous prime is 861404543983. The next prime is 861404544029. The reversal of 861404544000 is 445404168.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (3520).

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

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 319 ways as a sum of consecutive naturals, for example, 10378367959 + ... + 10378368041.

Almost surely, 2^861404544000 is an apocalyptic number.

861404544000 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 861404544000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2181103981056).

861404544000 is an abundant number, since it is smaller than the sum of its proper divisors (3500803418112).

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

861404544000 is a wasteful number, since it uses less digits than its factorization.

861404544000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 161 (or 124 counting only the distinct ones).

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

Adding to 861404544000 its reverse (445404168), we get a palindrome (861849948168).

The spelling of 861404544000 in words is "eight hundred sixty-one billion, four hundred four million, five hundred forty-four thousand".