6900721 has 4 divisors (see below), whose sum is σ = 6917092. Its totient is φ = 6884352.

The previous prime is 6900689. The next prime is 6900727. The reversal of 6900721 is 1270096.

6900721 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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 2640625 + 4260096 = 1625^2 + 2064^2 .

It is a cyclic number.

It is not a de Polignac number, because 6900721 - 2⁵ = 6900689 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6900727) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7536 + ... + 8401.

It is an arithmetic number, because the mean of its divisors is an integer number (1729273).

Almost surely, 2^6900721 is an apocalyptic number.

It is an amenable number.

6900721 is a deficient number, since it is larger than the sum of its proper divisors (16371).

6900721 is a wasteful number, since it uses less digits than its factorization.

6900721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16370.

The product of its (nonzero) digits is 756, while the sum is 25.

The square root of 6900721 is about 2626.9223437323. The cubic root of 6900721 is about 190.3844569998.

The spelling of 6900721 in words is "six million, nine hundred thousand, seven hundred twenty-one".