6720665 has 16 divisors (see below), whose sum is σ = 9393408. Its totient is φ = 4520256.

The previous prime is 6720629. The next prime is 6720667. The reversal of 6720665 is 5660276.

It is a cyclic number.

It is not a de Polignac number, because 6720665 - 2⁶ = 6720601 is a prime.

It is a Duffinian number.

It is a Curzon 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 15 ways as a sum of consecutive naturals, for example, 44 + ... + 3666.

It is an arithmetic number, because the mean of its divisors is an integer number (587088).

Almost surely, 2^6720665 is an apocalyptic number.

It is an amenable number.

6720665 is a deficient number, since it is larger than the sum of its proper divisors (2672743).

6720665 is a wasteful number, since it uses less digits than its factorization.

6720665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3688.

The product of its (nonzero) digits is 15120, while the sum is 32.

The square root of 6720665 is about 2592.4245408497. The cubic root of 6720665 is about 188.7139837425.

The spelling of 6720665 in words is "six million, seven hundred twenty thousand, six hundred sixty-five".