21553555204393 has 2 divisors, whose sum is σ = 21553555204394. Its totient is φ = 21553555204392.

The previous prime is 21553555204373. The next prime is 21553555204477. The reversal of 21553555204393 is 39340255535512.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16571673172224 + 4981882032169 = 4070832^2 + 2232013^2 .

It is a cyclic number.

It is not a de Polignac number, because 21553555204393 - 2⁵ = 21553555204361 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21553555204393.

It is not a weakly prime, because it can be changed into another prime (21553555204333) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10776777602196 + 10776777602197.

It is an arithmetic number, because the mean of its divisors is an integer number (10776777602197).

Almost surely, 2^{21553555204393} is an apocalyptic number.

It is an amenable number.

21553555204393 is a deficient number, since it is larger than the sum of its proper divisors (1).

21553555204393 is an equidigital number, since it uses as much as digits as its factorization.

21553555204393 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12150000, while the sum is 52.

The spelling of 21553555204393 in words is "twenty-one trillion, five hundred fifty-three billion, five hundred fifty-five million, two hundred four thousand, three hundred ninety-three".