1221011220001 has 2 divisors, whose sum is σ = 1221011220002. Its totient is φ = 1221011220000.

The previous prime is 1221011219993. The next prime is 1221011220029. The reversal of 1221011220001 is 1000221101221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1022220080401 + 198791139600 = 1011049^2 + 445860^2 .

It is an emirp because it is prime and its reverse (1000221101221) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1221011220001 - 2³ = 1221011219993 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221011220061) 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, 610505610000 + 610505610001.

It is an arithmetic number, because the mean of its divisors is an integer number (610505610001).

Almost surely, 2^{1221011220001} is an apocalyptic number.

It is an amenable number.

1221011220001 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221011220001 is an equidigital number, since it uses as much as digits as its factorization.

1221011220001 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 1221011220001 its reverse (1000221101221), we get a palindrome (2221232321222).

The spelling of 1221011220001 in words is "one trillion, two hundred twenty-one billion, eleven million, two hundred twenty thousand, one".