6812821 has 2 divisors, whose sum is σ = 6812822. Its totient is φ = 6812820.

The previous prime is 6812809. The next prime is 6812833. The reversal of 6812821 is 1282186.

It is a balanced prime because it is at equal distance from previous prime (6812809) and next prime (6812833).

It can be written as a sum of positive squares in only one way, i.e., 3960100 + 2852721 = 1990^2 + 1689^2 .

It is a cyclic number.

It is not a de Polignac number, because 6812821 - 2⁷ = 6812693 is a prime.

It is a Chen prime.

It is an Ulam number.

6812821 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 6812821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6812891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3406410 + 3406411.

It is an arithmetic number, because the mean of its divisors is an integer number (3406411).

Almost surely, 2^6812821 is an apocalyptic number.

It is an amenable number.

6812821 is a deficient number, since it is larger than the sum of its proper divisors (1).

6812821 is an equidigital number, since it uses as much as digits as its factorization.

6812821 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1536, while the sum is 28.

The square root of 6812821 is about 2610.1381189508. The cubic root of 6812821 is about 189.5726405863.

The spelling of 6812821 in words is "six million, eight hundred twelve thousand, eight hundred twenty-one".