6661680 has 80 divisors (see below), whose sum is σ = 21186144. Its totient is φ = 1730560.

The previous prime is 6661661. The next prime is 6661687. The reversal of 6661680 is 861666.

It is a tau number, because it is divible by the number of its divisors (80).

It is not an unprimeable number, because it can be changed into a prime (6661687) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9502 + ... + 10178.

Almost surely, 2^6661680 is an apocalyptic number.

6661680 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 6661680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (10593072).

6661680 is an abundant number, since it is smaller than the sum of its proper divisors (14524464).

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

6661680 is a wasteful number, since it uses less digits than its factorization.

6661680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 734 (or 728 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 6661680 is about 2581.0230529772. The cubic root of 6661680 is about 188.1602677411.

It can be divided in two parts, 666 and 1680, that added together give a triangular number (2346 = T₆₈).

The spelling of 6661680 in words is "six million, six hundred sixty-one thousand, six hundred eighty".