866523840 has 504 divisors, whose sum is σ = 3497305680. Its totient is φ = 181149696.

The previous prime is 866523793. The next prime is 866523869. The reversal of 866523840 is 48325668.

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 = 866523792 and 866523801.

It is a congruent number.

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 71 ways as a sum of consecutive naturals, for example, 7949706 + ... + 7949814.

Almost surely, 2^866523840 is an apocalyptic number.

866523840 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 866523840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1748652840).

866523840 is an abundant number, since it is smaller than the sum of its proper divisors (2630781840).

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

866523840 is a wasteful number, since it uses less digits than its factorization.

866523840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 169 (or 139 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 42.

The square root of 866523840 is about 29436.7769974907. The cubic root of 866523840 is about 953.3671246057.

The spelling of 866523840 in words is "eight hundred sixty-six million, five hundred twenty-three thousand, eight hundred forty".