21544203193 has 2 divisors, whose sum is σ = 21544203194. Its totient is φ = 21544203192.

The previous prime is 21544203181. The next prime is 21544203203. The reversal of 21544203193 is 39130244512.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14527963024 + 7016240169 = 120532^2 + 83763^2 .

It is a cyclic number.

It is not a de Polignac number, because 21544203193 - 2²¹ = 21542106041 is a prime.

It is not a weakly prime, because it can be changed into another prime (21544203133) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10772101596 + 10772101597.

It is an arithmetic number, because the mean of its divisors is an integer number (10772101597).

Almost surely, 2^21544203193 is an apocalyptic number.

It is an amenable number.

21544203193 is a deficient number, since it is larger than the sum of its proper divisors (1).

21544203193 is an equidigital number, since it uses as much as digits as its factorization.

21544203193 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 25920, while the sum is 34.

The spelling of 21544203193 in words is "twenty-one billion, five hundred forty-four million, two hundred three thousand, one hundred ninety-three".