1131205123 has 4 divisors (see below), whose sum is σ = 1131738088. Its totient is φ = 1130672160.

The previous prime is 1131205093. The next prime is 1131205133. The reversal of 1131205123 is 3215021311.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3215021311 = 1597 ⋅2013163.

It is a cyclic number.

It is not a de Polignac number, because 1131205123 - 2¹⁷ = 1131074051 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 1131205123.

It is not an unprimeable number, because it can be changed into a prime (1131205133) 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 in 3 ways as a sum of consecutive naturals, for example, 263286 + ... + 267547.

It is an arithmetic number, because the mean of its divisors is an integer number (282934522).

Almost surely, 2^1131205123 is an apocalyptic number.

1131205123 is a deficient number, since it is larger than the sum of its proper divisors (532965).

1131205123 is an equidigital number, since it uses as much as digits as its factorization.

1131205123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 532964.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 1131205123 is about 33633.3929748398. The cubic root of 1131205123 is about 1041.9505808400.

Adding to 1131205123 its reverse (3215021311), we get a palindrome (4346226434).

The spelling of 1131205123 in words is "one billion, one hundred thirty-one million, two hundred five thousand, one hundred twenty-three".