1243055909 has 2 divisors, whose sum is σ = 1243055910.
Its totient is φ = 1243055908.
The previous prime is 1243055843. The next prime is 1243055921. The reversal of 1243055909 is 9095503421.
It is a strong prime.
It can be written as a sum of positive squares in only one way, i.e., 1135353025 + 107702884 = 33695^2 + 10378^2
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-1243055909 is a prime.
It is a congruent number.
It is not a weakly prime, because it can be changed into another prime (1243055509) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 621527954 + 621527955.
It is an arithmetic number, because the mean of its divisors is an integer number (621527955).
Almost surely, 21243055909 is an apocalyptic number.
It is an amenable number.
1243055909 is a deficient number, since it is larger than the sum of its proper divisors (1).
1243055909 is an equidigital number, since it uses as much as digits as its factorization.
1243055909 is an evil number, because the sum of its binary digits is even.
The product of its (nonzero) digits is 48600, while the sum is 38.
The square root of 1243055909 is about 35256.9980145786.
The cubic root of 1243055909 is about 1075.2188943831.
The spelling of 1243055909 in words is "one billion, two hundred forty-three million, fifty-five thousand, nine hundred nine".