861644680080 has 640 divisors, whose sum is σ = 2931240960000. Its totient is φ = 208836526080.

The previous prime is 861644680067. The next prime is 861644680103. The reversal of 861644680080 is 80086446168.

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 127 ways as a sum of consecutive naturals, for example, 1438471621 + ... + 1438472219.

It is an arithmetic number, because the mean of its divisors is an integer number (4580064000).

Almost surely, 2^861644680080 is an apocalyptic number.

861644680080 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 861644680080, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1465620480000).

861644680080 is an abundant number, since it is smaller than the sum of its proper divisors (2069596279920).

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

861644680080 is a wasteful number, since it uses less digits than its factorization.

861644680080 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 847 (or 841 counting only the distinct ones).

The product of its (nonzero) digits is 1769472, while the sum is 51.

The spelling of 861644680080 in words is "eight hundred sixty-one billion, six hundred forty-four million, six hundred eighty thousand, eighty".