1242943309 has 2 divisors, whose sum is σ = 1242943310. Its totient is φ = 1242943308.

The previous prime is 1242943307. The next prime is 1242943313. The reversal of 1242943309 is 9033492421.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1072562500 + 170380809 = 32750^2 + 13053^2 .

It is an emirp because it is prime and its reverse (9033492421) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1242943309 - 2¹ = 1242943307 is a prime.

Together with 1242943307, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1242943307) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 621471654 + 621471655.

It is an arithmetic number, because the mean of its divisors is an integer number (621471655).

Almost surely, 2^1242943309 is an apocalyptic number.

It is an amenable number.

1242943309 is a deficient number, since it is larger than the sum of its proper divisors (1).

1242943309 is an equidigital number, since it uses as much as digits as its factorization.

1242943309 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 46656, while the sum is 37.

The square root of 1242943309 is about 35255.4011323088. The cubic root of 1242943309 is about 1075.1864278082.

The spelling of 1242943309 in words is "one billion, two hundred forty-two million, nine hundred forty-three thousand, three hundred nine".