6821261 has 2 divisors, whose sum is σ = 6821262. Its totient is φ = 6821260.

The previous prime is 6821257. The next prime is 6821263. The reversal of 6821261 is 1621286.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4541161 + 2280100 = 2131^2 + 1510^2 .

It is a cyclic number.

It is not a de Polignac number, because 6821261 - 2² = 6821257 is a prime.

It is a Sophie Germain prime.

Together with 6821263, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is equal to p₄₆₅₂₄₅ and since 6821261 and 465245 have the same sum of digits, it is a Honaker prime.

It is a self number, because there is not a number n which added to its sum of digits gives 6821261.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6821263) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3410630 + 3410631.

It is an arithmetic number, because the mean of its divisors is an integer number (3410631).

Almost surely, 2^6821261 is an apocalyptic number.

It is an amenable number.

6821261 is a deficient number, since it is larger than the sum of its proper divisors (1).

6821261 is an equidigital number, since it uses as much as digits as its factorization.

6821261 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1152, while the sum is 26.

The square root of 6821261 is about 2611.7543912091. The cubic root of 6821261 is about 189.6508917164.

The spelling of 6821261 in words is "six million, eight hundred twenty-one thousand, two hundred sixty-one".