820108691309 has 2 divisors, whose sum is σ = 820108691310. Its totient is φ = 820108691308.

The previous prime is 820108691293. The next prime is 820108691317. The reversal of 820108691309 is 903196801028.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 513279109225 + 306829582084 = 716435^2 + 553922^2 .

It is a cyclic number.

It is not a de Polignac number, because 820108691309 - 2⁴ = 820108691293 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (820108691609) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410054345654 + 410054345655.

It is an arithmetic number, because the mean of its divisors is an integer number (410054345655).

Almost surely, 2^820108691309 is an apocalyptic number.

It is an amenable number.

820108691309 is a deficient number, since it is larger than the sum of its proper divisors (1).

820108691309 is an equidigital number, since it uses as much as digits as its factorization.

820108691309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 186624, while the sum is 47.

The spelling of 820108691309 in words is "eight hundred twenty billion, one hundred eight million, six hundred ninety-one thousand, three hundred nine".