6661720 has 64 divisors (see below), whose sum is σ = 16873920. Its totient is φ = 2348544.

The previous prime is 6661709. The next prime is 6661727. The reversal of 6661720 is 271666.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6661727) 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, 11682 + ... + 12238.

It is an arithmetic number, because the mean of its divisors is an integer number (263655).

Almost surely, 2^6661720 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 6661720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (8436960).

6661720 is an abundant number, since it is smaller than the sum of its proper divisors (10212200).

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

6661720 is a wasteful number, since it uses less digits than its factorization.

6661720 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 604 (or 600 counting only the distinct ones).

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 6661720 is about 2581.0308018309. The cubic root of 6661720 is about 188.1606443425.

It can be divided in two parts, 6661 and 720, that added together give a triangular number (7381 = T₁₂₁).

The spelling of 6661720 in words is "six million, six hundred sixty-one thousand, seven hundred twenty".