1221289356901 has 2 divisors, whose sum is σ = 1221289356902. Its totient is φ = 1221289356900.

The previous prime is 1221289356863. The next prime is 1221289356923. The reversal of 1221289356901 is 1096539821221.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 623466580801 + 597822776100 = 789599^2 + 773190^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221289356901 - 2¹³ = 1221289348709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221289356601) 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, 610644678450 + 610644678451.

It is an arithmetic number, because the mean of its divisors is an integer number (610644678451).

Almost surely, 2^{1221289356901} is an apocalyptic number.

It is an amenable number.

1221289356901 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221289356901 is an equidigital number, since it uses as much as digits as its factorization.

1221289356901 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 466560, while the sum is 49.

The spelling of 1221289356901 in words is "one trillion, two hundred twenty-one billion, two hundred eighty-nine million, three hundred fifty-six thousand, nine hundred one".