1221020008909 has 2 divisors, whose sum is σ = 1221020008910. Its totient is φ = 1221020008908.

The previous prime is 1221020008883. The next prime is 1221020008961. The reversal of 1221020008909 is 9098000201221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1216174456809 + 4845552100 = 1102803^2 + 69610^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221020008909 - 2³¹ = 1218872525261 is a prime.

It is a super-2 number, since 2×1221020008909² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221020008609) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610510004454 + 610510004455.

It is an arithmetic number, because the mean of its divisors is an integer number (610510004455).

Almost surely, 2^{1221020008909} is an apocalyptic number.

It is an amenable number.

1221020008909 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221020008909 is an equidigital number, since it uses as much as digits as its factorization.

1221020008909 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 5184, while the sum is 34.

The spelling of 1221020008909 in words is "one trillion, two hundred twenty-one billion, twenty million, eight thousand, nine hundred nine".