861505377824 has 192 divisors, whose sum is σ = 2119193395200. Its totient is φ = 335679095808.

The previous prime is 861505377823. The next prime is 861505377851. The reversal of 861505377824 is 428773505168.

It is a Harshad number since it is a multiple of its sum of digits (56).

It is a self number, because there is not a number n which added to its sum of digits gives 861505377824.

It is not an unprimeable number, because it can be changed into a prime (861505377823) by changing a digit.

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 31 ways as a sum of consecutive naturals, for example, 51397157 + ... + 51413915.

It is an arithmetic number, because the mean of its divisors is an integer number (11037465600).

Almost surely, 2^861505377824 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 861505377824, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1059596697600).

861505377824 is an abundant number, since it is smaller than the sum of its proper divisors (1257688017376).

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

861505377824 is a wasteful number, since it uses less digits than its factorization.

861505377824 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17055 (or 17047 counting only the distinct ones).

The product of its (nonzero) digits is 11289600, while the sum is 56.

The spelling of 861505377824 in words is "eight hundred sixty-one billion, five hundred five million, three hundred seventy-seven thousand, eight hundred twenty-four".