203121344321221 has 2 divisors, whose sum is σ = 203121344321222. Its totient is φ = 203121344321220.

The previous prime is 203121344321197. The next prime is 203121344321309. The reversal of 203121344321221 is 122123443121302.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 200150030258721 + 2971314062500 = 14147439^2 + 1723750^2 .

It is a cyclic number.

It is not a de Polignac number, because 203121344321221 - 2¹⁹ = 203121343796933 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (203121344321821) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 101560672160610 + 101560672160611.

It is an arithmetic number, because the mean of its divisors is an integer number (101560672160611).

Almost surely, 2^{203121344321221} is an apocalyptic number.

It is an amenable number.

203121344321221 is a deficient number, since it is larger than the sum of its proper divisors (1).

203121344321221 is an equidigital number, since it uses as much as digits as its factorization.

203121344321221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 31.

Adding to 203121344321221 its reverse (122123443121302), we get a palindrome (325244787442523).

The spelling of 203121344321221 in words is "two hundred three trillion, one hundred twenty-one billion, three hundred forty-four million, three hundred twenty-one thousand, two hundred twenty-one".