6461821 has 2 divisors, whose sum is σ = 6461822. Its totient is φ = 6461820.

The previous prime is 6461803. The next prime is 6461831. The reversal of 6461821 is 1281646.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5336100 + 1125721 = 2310^2 + 1061^2 .

It is a cyclic number.

It is not a de Polignac number, because 6461821 - 2¹¹ = 6459773 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6461821.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6461801) 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, 3230910 + 3230911.

It is an arithmetic number, because the mean of its divisors is an integer number (3230911).

Almost surely, 2^6461821 is an apocalyptic number.

It is an amenable number.

6461821 is a deficient number, since it is larger than the sum of its proper divisors (1).

6461821 is an equidigital number, since it uses as much as digits as its factorization.

6461821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2304, while the sum is 28.

The square root of 6461821 is about 2542.0112116196. The cubic root of 6461821 is about 186.2594463926.

The spelling of 6461821 in words is "six million, four hundred sixty-one thousand, eight hundred twenty-one".