320338321791821 has 2 divisors, whose sum is σ = 320338321791822. Its totient is φ = 320338321791820.

The previous prime is 320338321791793. The next prime is 320338321791827. The reversal of 320338321791821 is 128197123833023.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 206629987636900 + 113708334154921 = 14374630^2 + 10663411^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-320338321791821 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (320338321791827) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160169160895910 + 160169160895911.

It is an arithmetic number, because the mean of its divisors is an integer number (160169160895911).

Almost surely, 2^{320338321791821} is an apocalyptic number.

It is an amenable number.

320338321791821 is a deficient number, since it is larger than the sum of its proper divisors (1).

320338321791821 is an equidigital number, since it uses as much as digits as its factorization.

320338321791821 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2612736, while the sum is 53.

The spelling of 320338321791821 in words is "three hundred twenty trillion, three hundred thirty-eight billion, three hundred twenty-one million, seven hundred ninety-one thousand, eight hundred twenty-one".