2166723389 has 4 divisors (see below), whose sum is σ = 2294177724. Its totient is φ = 2039269056.

The previous prime is 2166723329. The next prime is 2166723413. The reversal of 2166723389 is 9833276612.

It is a happy number.

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

It can be written as a sum of positive squares in 2 ways, for example, as 813219289 + 1353504100 = 28517^2 + 36790^2 .

It is a cyclic number.

It is not a de Polignac number, because 2166723389 - 2¹² = 2166719293 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2166723329) 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, 63727142 + ... + 63727175.

It is an arithmetic number, because the mean of its divisors is an integer number (573544431).

Almost surely, 2^2166723389 is an apocalyptic number.

It is an amenable number.

2166723389 is a deficient number, since it is larger than the sum of its proper divisors (127454335).

2166723389 is a wasteful number, since it uses less digits than its factorization.

2166723389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 127454334.

The product of its digits is 653184, while the sum is 47.

The square root of 2166723389 is about 46548.0761041743. The cubic root of 2166723389 is about 1294.0006380255. Note that the first 3 decimals are identical.

The spelling of 2166723389 in words is "two billion, one hundred sixty-six million, seven hundred twenty-three thousand, three hundred eighty-nine".