6720661 has 8 divisors (see below), whose sum is σ = 7490880. Its totient is φ = 5992128.

The previous prime is 6720629. The next prime is 6720667. The reversal of 6720661 is 1660276.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6720661 - 2⁵ = 6720629 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6720667) 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 7 ways as a sum of consecutive naturals, for example, 10081 + ... + 10726.

It is an arithmetic number, because the mean of its divisors is an integer number (936360).

Almost surely, 2^6720661 is an apocalyptic number.

It is an amenable number.

6720661 is a deficient number, since it is larger than the sum of its proper divisors (770219).

6720661 is a wasteful number, since it uses less digits than its factorization.

6720661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20843.

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

The square root of 6720661 is about 2592.4237693710. The cubic root of 6720661 is about 188.7139463029.

It can be divided in two parts, 6720 and 661, that added together give a triangular number (7381 = T₁₂₁).

The spelling of 6720661 in words is "six million, seven hundred twenty thousand, six hundred sixty-one".