5215806666 has 72 divisors (see below), whose sum is σ = 13233358944. Its totient is φ = 1480323600.

The previous prime is 5215806619. The next prime is 5215806667. The reversal of 5215806666 is 6666085125.

It is a happy number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (5215806667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 113601 + ... + 152763.

It is an arithmetic number, because the mean of its divisors is an integer number (183796652).

Almost surely, 2^5215806666 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 5215806666, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (6616679472).

5215806666 is an abundant number, since it is smaller than the sum of its proper divisors (8017552278).

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

5215806666 is a wasteful number, since it uses less digits than its factorization.

5215806666 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39336 (or 39326 counting only the distinct ones).

The product of its (nonzero) digits is 518400, while the sum is 45.

The square root of 5215806666 is about 72220.5418561783. The cubic root of 5215806666 is about 1734.2318647652.

The spelling of 5215806666 in words is "five billion, two hundred fifteen million, eight hundred six thousand, six hundred sixty-six".