1243686109 has 2 divisors, whose sum is σ = 1243686110. Its totient is φ = 1243686108.

The previous prime is 1243686091. The next prime is 1243686127. The reversal of 1243686109 is 9016863421.

Together with previous prime (1243686091) it forms an Ormiston pair, because they use the same digits, order apart.

It is a balanced prime because it is at equal distance from previous prime (1243686091) and next prime (1243686127).

It can be written as a sum of positive squares in only one way, i.e., 994140900 + 249545209 = 31530^2 + 15797^2 .

It is a cyclic number.

It is not a de Polignac number, because 1243686109 - 2²⁵ = 1210131677 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1243686139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 621843054 + 621843055.

It is an arithmetic number, because the mean of its divisors is an integer number (621843055).

Almost surely, 2^1243686109 is an apocalyptic number.

It is an amenable number.

1243686109 is a deficient number, since it is larger than the sum of its proper divisors (1).

1243686109 is an equidigital number, since it uses as much as digits as its factorization.

1243686109 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 62208, while the sum is 40.

The square root of 1243686109 is about 35265.9341149501. The cubic root of 1243686109 is about 1075.4005672172.

The spelling of 1243686109 in words is "one billion, two hundred forty-three million, six hundred eighty-six thousand, one hundred nine".