6611821 has 2 divisors, whose sum is σ = 6611822. Its totient is φ = 6611820.

The previous prime is 6611807. The next prime is 6611849. The reversal of 6611821 is 1281166.

6611821 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6375625 + 236196 = 2525^2 + 486^2 .

It is a cyclic number.

It is not a de Polignac number, because 6611821 - 2¹³ = 6603629 is a prime.

6611821 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6611881) 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 as a sum of consecutive naturals, namely, 3305910 + 3305911.

It is an arithmetic number, because the mean of its divisors is an integer number (3305911).

Almost surely, 2^6611821 is an apocalyptic number.

It is an amenable number.

6611821 is a deficient number, since it is larger than the sum of its proper divisors (1).

6611821 is an equidigital number, since it uses as much as digits as its factorization.

6611821 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 6611821 is about 2571.3461455043. The cubic root of 6611821 is about 187.6896664478.

Adding to 6611821 its reverse (1281166), we get a palindrome (7892987).

The spelling of 6611821 in words is "six million, six hundred eleven thousand, eight hundred twenty-one".