861880220880 has 320 divisors, whose sum is σ = 3177341779968. Its totient is φ = 189170841600.

The previous prime is 861880220849. The next prime is 861880220897. The reversal of 861880220880 is 88022088168.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 4081905 + ... + 4287855.

Almost surely, 2^861880220880 is an apocalyptic number.

861880220880 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 861880220880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1588670889984).

861880220880 is an abundant number, since it is smaller than the sum of its proper divisors (2315461559088).

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

861880220880 is a wasteful number, since it uses less digits than its factorization.

861880220880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 206074 (or 206068 counting only the distinct ones).

The product of its (nonzero) digits is 786432, while the sum is 51.

The spelling of 861880220880 in words is "eight hundred sixty-one billion, eight hundred eighty million, two hundred twenty thousand, eight hundred eighty".