820378861061 has 2 divisors, whose sum is σ = 820378861062. Its totient is φ = 820378861060.

The previous prime is 820378860941. The next prime is 820378861063. The reversal of 820378861061 is 160168873028.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 480817428100 + 339561432961 = 693410^2 + 582719^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-820378861061 is a prime.

Together with 820378861063, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (820378861063) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410189430530 + 410189430531.

It is an arithmetic number, because the mean of its divisors is an integer number (410189430531).

Almost surely, 2^820378861061 is an apocalyptic number.

It is an amenable number.

820378861061 is a deficient number, since it is larger than the sum of its proper divisors (1).

820378861061 is an equidigital number, since it uses as much as digits as its factorization.

820378861061 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 774144, while the sum is 50.

The spelling of 820378861061 in words is "eight hundred twenty billion, three hundred seventy-eight million, eight hundred sixty-one thousand, sixty-one".