1261313355243 has 16 divisors (see below), whose sum is σ = 1685639120256. Its totient is φ = 838932194880.

The previous prime is 1261313355223. The next prime is 1261313355251. The reversal of 1261313355243 is 3425533131621.

It is not a de Polignac number, because 1261313355243 - 2¹³ = 1261313347051 is a prime.

It is a super-2 number, since 2×1261313355243² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (1261313355223) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8501980 + ... + 8649062.

It is an arithmetic number, because the mean of its divisors is an integer number (105352445016).

Almost surely, 2^{1261313355243} is an apocalyptic number.

1261313355243 is a deficient number, since it is larger than the sum of its proper divisors (424325765013).

1261313355243 is a wasteful number, since it uses less digits than its factorization.

1261313355243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 153674.

The product of its digits is 194400, while the sum is 39.

Adding to 1261313355243 its reverse (3425533131621), we get a palindrome (4686846486864).

The spelling of 1261313355243 in words is "one trillion, two hundred sixty-one billion, three hundred thirteen million, three hundred fifty-five thousand, two hundred forty-three".