6534666821 has 2 divisors, whose sum is σ = 6534666822. Its totient is φ = 6534666820.

The previous prime is 6534666791. The next prime is 6534666833. The reversal of 6534666821 is 1286664356.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4053232225 + 2481434596 = 63665^2 + 49814^2 .

It is a cyclic number.

It is not a de Polignac number, because 6534666821 - 2²² = 6530472517 is a prime.

It is a super-2 number, since 2×6534666821² = 85403740922956492082, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6534666841) 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, 3267333410 + 3267333411.

It is an arithmetic number, because the mean of its divisors is an integer number (3267333411).

Almost surely, 2^6534666821 is an apocalyptic number.

It is an amenable number.

6534666821 is a deficient number, since it is larger than the sum of its proper divisors (1).

6534666821 is an equidigital number, since it uses as much as digits as its factorization.

6534666821 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1244160, while the sum is 47.

The square root of 6534666821 is about 80837.2860813622. The cubic root of 6534666821 is about 1869.5674999471.

The spelling of 6534666821 in words is "six billion, five hundred thirty-four million, six hundred sixty-six thousand, eight hundred twenty-one".