1221020210309 has 2 divisors, whose sum is σ = 1221020210310. Its totient is φ = 1221020210308.

The previous prime is 1221020210279. The next prime is 1221020210327. The reversal of 1221020210309 is 9030120201221.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 903301978084 + 317718232225 = 950422^2 + 563665^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1221020210309 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221020218309) 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, 610510105154 + 610510105155.

It is an arithmetic number, because the mean of its divisors is an integer number (610510105155).

Almost surely, 2^{1221020210309} is an apocalyptic number.

It is an amenable number.

1221020210309 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221020210309 is an equidigital number, since it uses as much as digits as its factorization.

1221020210309 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 23.

The spelling of 1221020210309 in words is "one trillion, two hundred twenty-one billion, twenty million, two hundred ten thousand, three hundred nine".