1311123251 has 4 divisors (see below), whose sum is σ = 1311245904. Its totient is φ = 1311000600.

The previous prime is 1311123227. The next prime is 1311123271. The reversal of 1311123251 is 1523211131.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 1311123251 - 2³⁰ = 237381427 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1311123221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 43580 + ... + 67241.

It is an arithmetic number, because the mean of its divisors is an integer number (327811476).

Almost surely, 2^1311123251 is an apocalyptic number.

1311123251 is a deficient number, since it is larger than the sum of its proper divisors (122653).

1311123251 is a wasteful number, since it uses less digits than its factorization.

1311123251 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 122652.

The product of its digits is 180, while the sum is 20.

The square root of 1311123251 is about 36209.4359387163. The cubic root of 1311123251 is about 1094.4968257311.

Adding to 1311123251 its reverse (1523211131), we get a palindrome (2834334382).

The spelling of 1311123251 in words is "one billion, three hundred eleven million, one hundred twenty-three thousand, two hundred fifty-one".