6811621 has 2 divisors, whose sum is σ = 6811622. Its totient is φ = 6811620.

The previous prime is 6811619. The next prime is 6811627. The reversal of 6811621 is 1261186.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 5085025 + 1726596 = 2255^2 + 1314^2 .

It is a cyclic number.

It is not a de Polignac number, because 6811621 - 2¹ = 6811619 is a prime.

Together with 6811619, it forms a pair of twin primes.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6811627) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3405810 + 3405811.

It is an arithmetic number, because the mean of its divisors is an integer number (3405811).

Almost surely, 2^6811621 is an apocalyptic number.

It is an amenable number.

6811621 is a deficient number, since it is larger than the sum of its proper divisors (1).

6811621 is an equidigital number, since it uses as much as digits as its factorization.

6811621 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 576, while the sum is 25.

The square root of 6811621 is about 2609.9082359347. The cubic root of 6811621 is about 189.5615095865.

The spelling of 6811621 in words is "six million, eight hundred eleven thousand, six hundred twenty-one".