820105547125321 has 2 divisors, whose sum is σ = 820105547125322. Its totient is φ = 820105547125320.

The previous prime is 820105547125223. The next prime is 820105547125421. The reversal of 820105547125321 is 123521745501028.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 818837626084921 + 1267921040400 = 28615339^2 + 1126020^2 .

It is a cyclic number.

It is not a de Polignac number, because 820105547125321 - 2⁴⁷ = 679368058769993 is a prime.

It is not a weakly prime, because it can be changed into another prime (820105547125421) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 410052773562660 + 410052773562661.

It is an arithmetic number, because the mean of its divisors is an integer number (410052773562661).

Almost surely, 2^{820105547125321} is an apocalyptic number.

It is an amenable number.

820105547125321 is a deficient number, since it is larger than the sum of its proper divisors (1).

820105547125321 is an equidigital number, since it uses as much as digits as its factorization.

820105547125321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 672000, while the sum is 46.

The spelling of 820105547125321 in words is "eight hundred twenty trillion, one hundred five billion, five hundred forty-seven million, one hundred twenty-five thousand, three hundred twenty-one".