2181168309 has 16 divisors (see below), whose sum is σ = 2918384000. Its totient is φ = 1449043776.

The previous prime is 2181168293. The next prime is 2181168337. The reversal of 2181168309 is 9038611812.

It is not a de Polignac number, because 2181168309 - 2⁴ = 2181168293 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 (2181161309) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1558392 + ... + 1559790.

It is an arithmetic number, because the mean of its divisors is an integer number (182399000).

Almost surely, 2^2181168309 is an apocalyptic number.

It is an amenable number.

2181168309 is a deficient number, since it is larger than the sum of its proper divisors (737215691).

2181168309 is a wasteful number, since it uses less digits than its factorization.

2181168309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2844.

The product of its (nonzero) digits is 20736, while the sum is 39.

The square root of 2181168309 is about 46702.9796586899. The cubic root of 2181168309 is about 1296.8698477399.

The spelling of 2181168309 in words is "two billion, one hundred eighty-one million, one hundred sixty-eight thousand, three hundred nine".