861222720000 has 800 divisors, whose sum is σ = 3069091726272. Its totient is φ = 213778432000.

The previous prime is 861222719989. The next prime is 861222720013. The reversal of 861222720000 is 27222168.

It is a tau number, because it is divible by the number of its divisors (800).

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a self number, because there is not a number n which added to its sum of digits gives 861222720000.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 1844159767 + ... + 1844160233.

Almost surely, 2^861222720000 is an apocalyptic number.

861222720000 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 861222720000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1534545863136).

861222720000 is an abundant number, since it is smaller than the sum of its proper divisors (2207869006272).

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

861222720000 is a wasteful number, since it uses less digits than its factorization.

861222720000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 638 (or 607 counting only the distinct ones).

The product of its (nonzero) digits is 5376, while the sum is 30.

Adding to 861222720000 its reverse (27222168), we get a palindrome (861249942168).

The spelling of 861222720000 in words is "eight hundred sixty-one billion, two hundred twenty-two million, seven hundred twenty thousand".