2166331243 has 4 divisors (see below), whose sum is σ = 2236212928. Its totient is φ = 2096449560.

The previous prime is 2166331231. The next prime is 2166331253. The reversal of 2166331243 is 3421336612.

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 2166331243 - 2⁹ = 2166330731 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (31), and also a Moran number because the ratio is a prime number: 69881653 = 2166331243 / (2 + 1 + 6 + 6 + 3 + 3 + 1 + 2 + 4 + 3).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2166331213) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34940796 + ... + 34940857.

It is an arithmetic number, because the mean of its divisors is an integer number (559053232).

Almost surely, 2^2166331243 is an apocalyptic number.

2166331243 is a deficient number, since it is larger than the sum of its proper divisors (69881685).

2166331243 is an equidigital number, since it uses as much as digits as its factorization.

2166331243 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 69881684.

The product of its digits is 15552, while the sum is 31.

The square root of 2166331243 is about 46543.8636449532. The cubic root of 2166331243 is about 1293.9225681016.

Adding to 2166331243 its reverse (3421336612), we get a palindrome (5587667855).

The spelling of 2166331243 in words is "two billion, one hundred sixty-six million, three hundred thirty-one thousand, two hundred forty-three".