6665940 has 72 divisors (see below), whose sum is σ = 20933640. Its totient is φ = 1714944.

The previous prime is 6665927. The next prime is 6665947. The reversal of 6665940 is 495666.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1077444 + 5588496 = 1038^2 + 2364^2 .

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

It is a junction number, because it is equal to n+sod(n) for n = 6665895 and 6665904.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6665947) 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 23 ways as a sum of consecutive naturals, for example, 4582 + ... + 5858.

It is an arithmetic number, because the mean of its divisors is an integer number (290745).

Almost surely, 2^6665940 is an apocalyptic number.

6665940 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 6665940, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10466820).

6665940 is an abundant number, since it is smaller than the sum of its proper divisors (14267700).

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

6665940 is a wasteful number, since it uses less digits than its factorization.

6665940 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1321 (or 1316 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The square root of 6665940 is about 2581.8481752419. The cubic root of 6665940 is about 188.2003673326.

The spelling of 6665940 in words is "six million, six hundred sixty-five thousand, nine hundred forty".