866755890 has 320 divisors, whose sum is σ = 3132138240. Its totient is φ = 166095360.

The previous prime is 866755873. The next prime is 866755891. The reversal of 866755890 is 98557668.

866755890 is a `hidden beast` number, since 86 + 6 + 7 + 558 + 9 + 0 = 666.

866755890 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (866755891) by changing a digit.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 810276 + ... + 811344.

It is an arithmetic number, because the mean of its divisors is an integer number (9787932).

Almost surely, 2^866755890 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 866755890, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1566069120).

866755890 is an abundant number, since it is smaller than the sum of its proper divisors (2265382350).

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

866755890 is a wasteful number, since it uses less digits than its factorization.

866755890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1119 (or 1110 counting only the distinct ones).

The product of its (nonzero) digits is 3628800, while the sum is 54.

The square root of 866755890 is about 29440.7182317280. The cubic root of 866755890 is about 953.4522190509.

The spelling of 866755890 in words is "eight hundred sixty-six million, seven hundred fifty-five thousand, eight hundred ninety".