866545827840 has 1600 divisors, whose sum is σ = 3946400092800. Its totient is φ = 176664084480.

The previous prime is 866545827827. The next prime is 866545827853. The reversal of 866545827840 is 48728545668.

866545827840 is a `hidden beast` number, since 8 + 6 + 6 + 5 + 4 + 582 + 7 + 8 + 40 = 666.

It is an interprime number because it is at equal distance from previous prime (866545827827) and next prime (866545827853).

It is a Harshad number since it is a multiple of its sum of digits (63).

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 16349921254 + ... + 16349921306.

It is an arithmetic number, because the mean of its divisors is an integer number (2466500058).

Almost surely, 2^866545827840 is an apocalyptic number.

866545827840 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 866545827840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1973200046400).

866545827840 is an abundant number, since it is smaller than the sum of its proper divisors (3079854264960).

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

866545827840 is an frugal number, since it uses more digits than its factorization.

866545827840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 126 (or 81 counting only the distinct ones).

The product of its (nonzero) digits is 103219200, while the sum is 63.

The spelling of 866545827840 in words is "eight hundred sixty-six billion, five hundred forty-five million, eight hundred twenty-seven thousand, eight hundred forty".