6721685 has 4 divisors (see below), whose sum is σ = 8066028. Its totient is φ = 5377344.

The previous prime is 6721669. The next prime is 6721691. The reversal of 6721685 is 5861276.

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 3976036 + 2745649 = 1994^2 + 1657^2 .

It is a cyclic number.

It is not a de Polignac number, because 6721685 - 2⁴ = 6721669 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 672164 + ... + 672173.

It is an arithmetic number, because the mean of its divisors is an integer number (2016507).

Almost surely, 2^6721685 is an apocalyptic number.

It is an amenable number.

6721685 is a deficient number, since it is larger than the sum of its proper divisors (1344343).

6721685 is a wasteful number, since it uses less digits than its factorization.

6721685 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1344342.

The product of its digits is 20160, while the sum is 35.

The square root of 6721685 is about 2592.6212604235. The cubic root of 6721685 is about 188.7235303437.

The spelling of 6721685 in words is "six million, seven hundred twenty-one thousand, six hundred eighty-five".