809555641 has 2 divisors, whose sum is σ = 809555642. Its totient is φ = 809555640.

The previous prime is 809555611. The next prime is 809555653. The reversal of 809555641 is 146555908.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 646227241 + 163328400 = 25421^2 + 12780^2 .

It is a cyclic number.

It is not a de Polignac number, because 809555641 - 2²⁹ = 272684729 is a prime.

It is not a weakly prime, because it can be changed into another prime (809555611) 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, 404777820 + 404777821.

It is an arithmetic number, because the mean of its divisors is an integer number (404777821).

Almost surely, 2^809555641 is an apocalyptic number.

It is an amenable number.

809555641 is a deficient number, since it is larger than the sum of its proper divisors (1).

809555641 is an equidigital number, since it uses as much as digits as its factorization.

809555641 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 216000, while the sum is 43.

The square root of 809555641 is about 28452.6912786822. The cubic root of 809555641 is about 931.9992605157. Note that the first 3 decimals are identical.

It can be divided in two parts, 8095 and 55641, that added together give a palindrome (63736).

The spelling of 809555641 in words is "eight hundred nine million, five hundred fifty-five thousand, six hundred forty-one".