1221240109 has 2 divisors, whose sum is σ = 1221240110. Its totient is φ = 1221240108.

The previous prime is 1221240107. The next prime is 1221240121. The reversal of 1221240109 is 9010421221.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1123724484 + 97515625 = 33522^2 + 9875^2 .

It is a cyclic number.

It is not a de Polignac number, because 1221240109 - 2¹ = 1221240107 is a prime.

Together with 1221240107, it forms a pair of twin primes.

It is a self number, because there is not a number n which added to its sum of digits gives 1221240109.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1221240107) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 610620054 + 610620055.

It is an arithmetic number, because the mean of its divisors is an integer number (610620055).

Almost surely, 2^1221240109 is an apocalyptic number.

It is an amenable number.

1221240109 is a deficient number, since it is larger than the sum of its proper divisors (1).

1221240109 is an equidigital number, since it uses as much as digits as its factorization.

1221240109 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 22.

The square root of 1221240109 is about 34946.2459929532. The cubic root of 1221240109 is about 1068.8916549058.

The spelling of 1221240109 in words is "one billion, two hundred twenty-one million, two hundred forty thousand, one hundred nine".