6665936640 has 288 divisors, whose sum is σ = 24593538816. Its totient is φ = 1520762880.

The previous prime is 6665936609. The next prime is 6665936647. The reversal of 6665936640 is 466395666.

It is a super-2 number, since 2×6665936640² = 88869422576988979200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (51).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6665936647) by changing a digit.

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, 713439 + ... + 722721.

It is an arithmetic number, because the mean of its divisors is an integer number (85394232).

Almost surely, 2^6665936640 is an apocalyptic number.

6665936640 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 6665936640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (12296769408).

6665936640 is an abundant number, since it is smaller than the sum of its proper divisors (17927602176).

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

6665936640 is a wasteful number, since it uses less digits than its factorization.

6665936640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9335 (or 9321 counting only the distinct ones).

The product of its (nonzero) digits is 4199040, while the sum is 51.

The square root of 6665936640 is about 81645.1874883021. The cubic root of 6665936640 is about 1882.0033571148.

The spelling of 6665936640 in words is "six billion, six hundred sixty-five million, nine hundred thirty-six thousand, six hundred forty".