1221000100121 has 2 divisors, whose sum is σ = 1221000100122. Its totient is φ = 1221000100120.

The previous prime is 1221000100091. The next prime is 1221000100147. The reversal of 1221000100121 is 1210010001221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 820392120025 + 400607980096 = 905755^2 + 632936^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221000100121 - 2³⁰ = 1219926358297 is a prime.

It is not a weakly prime, because it can be changed into another prime (1221000105121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610500050060 + 610500050061.

It is an arithmetic number, because the mean of its divisors is an integer number (610500050061).

Almost surely, 2^{1221000100121} is an apocalyptic number.

It is an amenable number.

1221000100121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221000100121 is an equidigital number, since it uses as much as digits as its factorization.

1221000100121 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 8, while the sum is 11.

Adding to 1221000100121 its reverse (1210010001221), we get a palindrome (2431010101342).

The spelling of 1221000100121 in words is "one trillion, two hundred twenty-one billion, one hundred thousand, one hundred twenty-one".