6660840 has 64 divisors (see below), whose sum is σ = 20424960. Its totient is φ = 1736960.

The previous prime is 6660809. The next prime is 6660859. The reversal of 6660840 is 480666.

It is a happy number.

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 = 6660798 and 6660807.

It is an unprimeable number.

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, 5050 + ... + 6230.

It is an arithmetic number, because the mean of its divisors is an integer number (319140).

Almost surely, 2^6660840 is an apocalyptic number.

6660840 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 6660840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10212480).

6660840 is an abundant number, since it is smaller than the sum of its proper divisors (13764120).

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

6660840 is a wasteful number, since it uses less digits than its factorization.

6660840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1242 (or 1238 counting only the distinct ones).

The product of its (nonzero) digits is 6912, while the sum is 30.

The square root of 6660840 is about 2580.8603216757. The cubic root of 6660840 is about 188.1523587617.

It can be divided in two parts, 66 and 60840, that added together give a palindrome (60906).

The spelling of 6660840 in words is "six million, six hundred sixty thousand, eight hundred forty".