6640213536 has 144 divisors (see below), whose sum is σ = 20655075168. Its totient is φ = 2006784000.

The previous prime is 6640213529. The next prime is 6640213577. The reversal of 6640213536 is 6353120466.

6640213536 is a `hidden beast` number, since 6 + 640 + 2 + 1 + 3 + 5 + 3 + 6 = 666.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a self number, because there is not a number n which added to its sum of digits gives 6640213536.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1267755 + ... + 1272981.

It is an arithmetic number, because the mean of its divisors is an integer number (143438022).

Almost surely, 2^6640213536 is an apocalyptic number.

6640213536 is a gapful number since it is divisible by the number (66) 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 6640213536, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10327537584).

6640213536 is an abundant number, since it is smaller than the sum of its proper divisors (14014861632).

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

6640213536 is a wasteful number, since it uses less digits than its factorization.

6640213536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5655 (or 5644 counting only the distinct ones).

The product of its (nonzero) digits is 77760, while the sum is 36.

The square root of 6640213536 is about 81487.5053980670. The cubic root of 6640213536 is about 1879.5794230462.

The spelling of 6640213536 in words is "six billion, six hundred forty million, two hundred thirteen thousand, five hundred thirty-six".