1261316242 has 4 divisors (see below), whose sum is σ = 1891974366. Its totient is φ = 630658120.

The previous prime is 1261316239. The next prime is 1261316249. The reversal of 1261316242 is 2426131621.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 2426131621 = 4507 ⋅538303.

It can be written as a sum of positive squares in only one way, i.e., 1258759441 + 2556801 = 35479^2 + 1599^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 1261316242.

It is not an unprimeable number, because it can be changed into a prime (1261316249) 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, 315329059 + ... + 315329062.

Almost surely, 2^1261316242 is an apocalyptic number.

1261316242 is a deficient number, since it is larger than the sum of its proper divisors (630658124).

1261316242 is an equidigital number, since it uses as much as digits as its factorization.

1261316242 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 630658123.

The product of its digits is 3456, while the sum is 28.

The square root of 1261316242 is about 35515.0143178910. The cubic root of 1261316242 is about 1080.4582651695.

Adding to 1261316242 its reverse (2426131621), we get a palindrome (3687447863).

The spelling of 1261316242 in words is "one billion, two hundred sixty-one million, three hundred sixteen thousand, two hundred forty-two".