1220203710721 has 2 divisors, whose sum is σ = 1220203710722. Its totient is φ = 1220203710720.

The previous prime is 1220203710629. The next prime is 1220203710731. The reversal of 1220203710721 is 1270173020221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 832154450625 + 388049260096 = 912225^2 + 622936^2 .

It is a cyclic number.

It is not a de Polignac number, because 1220203710721 - 2¹¹ = 1220203708673 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1220203710721.

It is not a weakly prime, because it can be changed into another prime (1220203710731) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610101855360 + 610101855361.

It is an arithmetic number, because the mean of its divisors is an integer number (610101855361).

Almost surely, 2^{1220203710721} is an apocalyptic number.

It is an amenable number.

1220203710721 is a deficient number, since it is larger than the sum of its proper divisors (1).

1220203710721 is an equidigital number, since it uses as much as digits as its factorization.

1220203710721 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2352, while the sum is 28.

Adding to 1220203710721 its reverse (1270173020221), we get a palindrome (2490376730942).

The spelling of 1220203710721 in words is "one trillion, two hundred twenty billion, two hundred three million, seven hundred ten thousand, seven hundred twenty-one".