6861581 has 2 divisors, whose sum is σ = 6861582. Its totient is φ = 6861580.

The previous prime is 6861559. The next prime is 6861583. The reversal of 6861581 is 1851686.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5248681 + 1612900 = 2291^2 + 1270^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-6861581 is a prime.

It is a super-3 number, since 3×6861581³ (a number of 21 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Sophie Germain prime.

Together with 6861583, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6861583) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3430790 + 3430791.

It is an arithmetic number, because the mean of its divisors is an integer number (3430791).

Almost surely, 2^6861581 is an apocalyptic number.

It is an amenable number.

6861581 is a deficient number, since it is larger than the sum of its proper divisors (1).

6861581 is an equidigital number, since it uses as much as digits as its factorization.

6861581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 11520, while the sum is 35.

The square root of 6861581 is about 2619.4619676567. The cubic root of 6861581 is about 190.0238289596.

The spelling of 6861581 in words is "six million, eight hundred sixty-one thousand, five hundred eighty-one".