861251211792 has 480 divisors, whose sum is σ = 2595478878720. Its totient is φ = 266139095040.

The previous prime is 861251211781. The next prime is 861251211817. The reversal of 861251211792 is 297112152168.

861251211792 is a `hidden beast` number, since 8 + 6 + 12 + 512 + 117 + 9 + 2 = 666.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 3178048617 + ... + 3178048887.

It is an arithmetic number, because the mean of its divisors is an integer number (5407247664).

Almost surely, 2^861251211792 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 861251211792, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1297739439360).

861251211792 is an abundant number, since it is smaller than the sum of its proper divisors (1734227666928).

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

861251211792 is a wasteful number, since it uses less digits than its factorization.

861251211792 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 623 (or 614 counting only the distinct ones).

The product of its digits is 120960, while the sum is 45.

The spelling of 861251211792 in words is "eight hundred sixty-one billion, two hundred fifty-one million, two hundred eleven thousand, seven hundred ninety-two".