1165821243 has 4 divisors (see below), whose sum is σ = 1554428328. Its totient is φ = 777214160.

The previous prime is 1165821233. The next prime is 1165821277. The reversal of 1165821243 is 3421285611.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 3421285611 = 3 ⋅1140428537.

It is a cyclic number.

It is not a de Polignac number, because 1165821243 - 2¹⁰ = 1165820219 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1165821233) 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, 194303538 + ... + 194303543.

It is an arithmetic number, because the mean of its divisors is an integer number (388607082).

Almost surely, 2^1165821243 is an apocalyptic number.

1165821243 is a deficient number, since it is larger than the sum of its proper divisors (388607085).

1165821243 is an equidigital number, since it uses as much as digits as its factorization.

1165821243 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 388607084.

The product of its digits is 11520, while the sum is 33.

The square root of 1165821243 is about 34144.1245751008. The cubic root of 1165821243 is about 1052.4722524529.

The spelling of 1165821243 in words is "one billion, one hundred sixty-five million, eight hundred twenty-one thousand, two hundred forty-three".