6720905 has 4 divisors (see below), whose sum is σ = 8065092. Its totient is φ = 5376720.

The previous prime is 6720887. The next prime is 6720911. The reversal of 6720905 is 5090276.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 5234944 + 1485961 = 2288^2 + 1219^2 .

It is not a de Polignac number, because 6720905 - 2⁶ = 6720841 is a prime.

It is a Duffinian number.

It is a Curzon number.

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 3 ways as a sum of consecutive naturals, for example, 672086 + ... + 672095.

It is an arithmetic number, because the mean of its divisors is an integer number (2016273).

Almost surely, 2^6720905 is an apocalyptic number.

It is an amenable number.

6720905 is a deficient number, since it is larger than the sum of its proper divisors (1344187).

6720905 is a wasteful number, since it uses less digits than its factorization.

6720905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1344186.

The product of its (nonzero) digits is 3780, while the sum is 29.

The square root of 6720905 is about 2592.4708291512. The cubic root of 6720905 is about 188.7162300885.

The spelling of 6720905 in words is "six million, seven hundred twenty thousand, nine hundred five".