1261242239 has 2 divisors, whose sum is σ = 1261242240. Its totient is φ = 1261242238.

The previous prime is 1261242221. The next prime is 1261242251. The reversal of 1261242239 is 9322421621.

It is a strong prime.

It is an emirp because it is prime and its reverse (9322421621) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1261242239 - 2¹⁶ = 1261176703 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1261242539) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 630621119 + 630621120.

It is an arithmetic number, because the mean of its divisors is an integer number (630621120).

Almost surely, 2^1261242239 is an apocalyptic number.

1261242239 is a deficient number, since it is larger than the sum of its proper divisors (1).

1261242239 is an equidigital number, since it uses as much as digits as its factorization.

1261242239 is an evil number, because the sum of its binary digits is even.

The product of its digits is 10368, while the sum is 32.

The square root of 1261242239 is about 35513.9724474748. The cubic root of 1261242239 is about 1080.4371341441.

The spelling of 1261242239 in words is "one billion, two hundred sixty-one million, two hundred forty-two thousand, two hundred thirty-nine".