866755940559120 has 640 divisors, whose sum is σ = 3059319990988800. Its totient is φ = 225497489817600.

The previous prime is 866755940559107. The next prime is 866755940559181. The reversal of 866755940559120 is 21955049557668.

866755940559120 is a `hidden beast` number, since 8 + 6 + 6 + 7 + 5 + 5 + 9 + 4 + 0 + 5 + 591 + 20 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 7091765371 + ... + 7091887589.

It is an arithmetic number, because the mean of its divisors is an integer number (4780187485920).

Almost surely, 2^{866755940559120} is an apocalyptic number.

866755940559120 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 866755940559120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1529659995494400).

866755940559120 is an abundant number, since it is smaller than the sum of its proper divisors (2192564050429680).

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

866755940559120 is a wasteful number, since it uses less digits than its factorization.

866755940559120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122796 (or 122784 counting only the distinct ones).

The product of its (nonzero) digits is 816480000, while the sum is 72.

The spelling of 866755940559120 in words is "eight hundred sixty-six trillion, seven hundred fifty-five billion, nine hundred forty million, five hundred fifty-nine thousand, one hundred twenty".