1221109709 has 2 divisors, whose sum is σ = 1221109710. Its totient is φ = 1221109708.

The previous prime is 1221109697. The next prime is 1221109741. The reversal of 1221109709 is 9079011221.

It is an a-pointer prime, because the next prime (1221109741) can be obtained adding 1221109709 to its sum of digits (32).

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 897901225 + 323208484 = 29965^2 + 17978^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221109709 - 2⁴ = 1221109693 is a prime.

It is a super-2 number, since 2×1221109709² = 2982217842828129362, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221109009) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610554854 + 610554855.

It is an arithmetic number, because the mean of its divisors is an integer number (610554855).

Almost surely, 2^1221109709 is an apocalyptic number.

It is an amenable number.

1221109709 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221109709 is an equidigital number, since it uses as much as digits as its factorization.

1221109709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2268, while the sum is 32.

The square root of 1221109709 is about 34944.3802205734. The cubic root of 1221109709 is about 1068.8536093072.

The spelling of 1221109709 in words is "one billion, two hundred twenty-one million, one hundred nine thousand, seven hundred nine".