1131173261 has 4 divisors (see below), whose sum is σ = 1148056512. Its totient is φ = 1114290012.

The previous prime is 1131173249. The next prime is 1131173273. The reversal of 1131173261 is 1623711311.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 1623711311 = 12113 ⋅134047.

It is an interprime number because it is at equal distance from previous prime (1131173249) and next prime (1131173273).

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1131173261 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1131173261.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1131173161) 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, 8441525 + ... + 8441658.

It is an arithmetic number, because the mean of its divisors is an integer number (287014128).

Almost surely, 2^1131173261 is an apocalyptic number.

It is an amenable number.

1131173261 is a deficient number, since it is larger than the sum of its proper divisors (16883251).

1131173261 is an equidigital number, since it uses as much as digits as its factorization.

1131173261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16883250.

The product of its digits is 756, while the sum is 26.

The square root of 1131173261 is about 33632.9193053473. The cubic root of 1131173261 is about 1041.9407980752.

Adding to 1131173261 its reverse (1623711311), we get a palindrome (2754884572).

The spelling of 1131173261 in words is "one billion, one hundred thirty-one million, one hundred seventy-three thousand, two hundred sixty-one".