6865721 has 4 divisors (see below), whose sum is σ = 7102500. Its totient is φ = 6628944.

The previous prime is 6865717. The next prime is 6865759. The reversal of 6865721 is 1275686.

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 3024121 + 3841600 = 1739^2 + 1960^2 .

It is a cyclic number.

It is not a de Polignac number, because 6865721 - 2² = 6865717 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6865711) 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 3 ways as a sum of consecutive naturals, for example, 118346 + ... + 118403.

It is an arithmetic number, because the mean of its divisors is an integer number (1775625).

Almost surely, 2^6865721 is an apocalyptic number.

It is an amenable number.

6865721 is a deficient number, since it is larger than the sum of its proper divisors (236779).

6865721 is a wasteful number, since it uses less digits than its factorization.

6865721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 236778.

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

The square root of 6865721 is about 2620.2520871092. The cubic root of 6865721 is about 190.0620388360.

Subtracting from 6865721 its sum of digits (35), we obtain a palindrome (6865686).

The spelling of 6865721 in words is "six million, eight hundred sixty-five thousand, seven hundred twenty-one".