1243242839 has 2 divisors, whose sum is σ = 1243242840. Its totient is φ = 1243242838.

The previous prime is 1243242823. The next prime is 1243242841. The reversal of 1243242839 is 9382423421.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1243242839 - 2⁴ = 1243242823 is a prime.

Together with 1243242841, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1243242899) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 621621419 + 621621420.

It is an arithmetic number, because the mean of its divisors is an integer number (621621420).

Almost surely, 2^1243242839 is an apocalyptic number.

1243242839 is a deficient number, since it is larger than the sum of its proper divisors (1).

1243242839 is an equidigital number, since it uses as much as digits as its factorization.

1243242839 is an evil number, because the sum of its binary digits is even.

The product of its digits is 82944, while the sum is 38.

The square root of 1243242839 is about 35259.6488780022. The cubic root of 1243242839 is about 1075.2727886052.

The spelling of 1243242839 in words is "one billion, two hundred forty-three million, two hundred forty-two thousand, eight hundred thirty-nine".