1311540243 has 16 divisors (see below), whose sum is σ = 1889954976. Its totient is φ = 804222720.

The previous prime is 1311540239. The next prime is 1311540253. The reversal of 1311540243 is 3420451131.

It is a happy number.

It is not a de Polignac number, because 1311540243 - 2² = 1311540239 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1311540233) 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, 48880 + ... + 70797.

It is an arithmetic number, because the mean of its divisors is an integer number (118122186).

Almost surely, 2^1311540243 is an apocalyptic number.

1311540243 is a gapful number since it is divisible by the number (13) formed by its first and last digit.

1311540243 is a deficient number, since it is larger than the sum of its proper divisors (578414733).

1311540243 is a wasteful number, since it uses less digits than its factorization.

1311540243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 119974.

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 1311540243 is about 36215.1935380718. The cubic root of 1311540243 is about 1094.6128453462.

Adding to 1311540243 its reverse (3420451131), we get a palindrome (4731991374).

The spelling of 1311540243 in words is "one billion, three hundred eleven million, five hundred forty thousand, two hundred forty-three".