6666440 has 64 divisors (see below), whose sum is σ = 16632000. Its totient is φ = 2384640.

The previous prime is 6666437. The next prime is 6666449. The reversal of 6666440 is 446666.

It is a happy number.

It is a hoax number, since the sum of its digits (32) coincides with the sum of the digits of its distinct prime factors.

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 6666397 and 6666406.

It is not an unprimeable number, because it can be changed into a prime (6666449) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47891 + ... + 48029.

It is an arithmetic number, because the mean of its divisors is an integer number (259875).

Almost surely, 2^6666440 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 6666440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8316000).

6666440 is an abundant number, since it is smaller than the sum of its proper divisors (9965560).

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

6666440 is a wasteful number, since it uses less digits than its factorization.

6666440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 270 (or 266 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 32.

The square root of 6666440 is about 2581.9450032873. The cubic root of 6666440 is about 188.2050727370.

The spelling of 6666440 in words is "six million, six hundred sixty-six thousand, four hundred forty".