861668280 has 192 divisors, whose sum is σ = 3168547200. Its totient is φ = 208863360.

The previous prime is 861668243. The next prime is 861668293. The reversal of 861668280 is 82866168.

861668280 is a `hidden beast` number, since 8 + 616 + 6 + 8 + 28 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 102891 + ... + 110949.

It is an arithmetic number, because the mean of its divisors is an integer number (16502850).

Almost surely, 2^861668280 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 861668280, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1584273600).

861668280 is an abundant number, since it is smaller than the sum of its proper divisors (2306878920).

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

861668280 is a wasteful number, since it uses less digits than its factorization.

861668280 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8096 (or 8080 counting only the distinct ones).

The product of its (nonzero) digits is 221184, while the sum is 45.

The square root of 861668280 is about 29354.1867541923. The cubic root of 861668280 is about 951.5830595427.

The spelling of 861668280 in words is "eight hundred sixty-one million, six hundred sixty-eight thousand, two hundred eighty".