6640205340 has 192 divisors, whose sum is σ = 19971173376. Its totient is φ = 1644453888.

The previous prime is 6640205311. The next prime is 6640205353. The reversal of 6640205340 is 435020466.

It is a Harshad number since it is a multiple of its sum of digits (30).

It is a junction number, because it is equal to n+sod(n) for n = 6640205298 and 6640205307.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 18810604 + ... + 18810956.

It is an arithmetic number, because the mean of its divisors is an integer number (104016528).

Almost surely, 2^6640205340 is an apocalyptic number.

6640205340 is a gapful number since it is divisible by the number (60) 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 6640205340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (9985586688).

6640205340 is an abundant number, since it is smaller than the sum of its proper divisors (13330968036).

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

6640205340 is a wasteful number, since it uses less digits than its factorization.

6640205340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 748 (or 746 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 30.

The square root of 6640205340 is about 81487.4551081331. The cubic root of 6640205340 is about 1879.5786497257.

The spelling of 6640205340 in words is "six billion, six hundred forty million, two hundred five thousand, three hundred forty".