866552778 has 96 divisors (see below), whose sum is σ = 2342785536. Its totient is φ = 225379584.

The previous prime is 866552777. The next prime is 866552789. The reversal of 866552778 is 877255668.

866552778 is a `hidden beast` number, since 86 + 6 + 552 + 7 + 7 + 8 = 666.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (866552777) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 115951 + ... + 123197.

It is an arithmetic number, because the mean of its divisors is an integer number (24404016).

Almost surely, 2^866552778 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 866552778, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1171392768).

866552778 is an abundant number, since it is smaller than the sum of its proper divisors (1476232758).

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

866552778 is a wasteful number, since it uses less digits than its factorization.

866552778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7348 (or 7345 counting only the distinct ones).

The product of its digits is 5644800, while the sum is 54.

The square root of 866552778 is about 29437.2685213829. The cubic root of 866552778 is about 953.3777372127.

The spelling of 866552778 in words is "eight hundred sixty-six million, five hundred fifty-two thousand, seven hundred seventy-eight".