321995204854861 has 2 divisors, whose sum is σ = 321995204854862. Its totient is φ = 321995204854860.

The previous prime is 321995204854849. The next prime is 321995204854879. The reversal of 321995204854861 is 168458402599123.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 232227273390025 + 89767931464836 = 15239005^2 + 9474594^2 .

It is a cyclic number.

It is not a de Polignac number, because 321995204854861 - 2⁴⁷ = 181257716499533 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (321995204857861) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160997602427430 + 160997602427431.

It is an arithmetic number, because the mean of its divisors is an integer number (160997602427431).

Almost surely, 2^{321995204854861} is an apocalyptic number.

It is an amenable number.

321995204854861 is a deficient number, since it is larger than the sum of its proper divisors (1).

321995204854861 is an equidigital number, since it uses as much as digits as its factorization.

321995204854861 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 149299200, while the sum is 67.

The spelling of 321995204854861 in words is "three hundred twenty-one trillion, nine hundred ninety-five billion, two hundred four million, eight hundred fifty-four thousand, eight hundred sixty-one".