866019840 has 320 divisors, whose sum is σ = 3217294080. Its totient is φ = 194641920.

The previous prime is 866019821. The next prime is 866019857. The reversal of 866019840 is 48910668.

866019840 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (320).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 866019792 and 866019801.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4784550 + ... + 4784730.

It is an arithmetic number, because the mean of its divisors is an integer number (10054044).

Almost surely, 2^866019840 is an apocalyptic number.

866019840 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 866019840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1608647040).

866019840 is an abundant number, since it is smaller than the sum of its proper divisors (2351274240).

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

866019840 is a wasteful number, since it uses less digits than its factorization.

866019840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 303 (or 287 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 42.

The square root of 866019840 is about 29428.2150325160. The cubic root of 866019840 is about 953.1822517468.

The spelling of 866019840 in words is "eight hundred sixty-six million, nineteen thousand, eight hundred forty".