2165894181 has 16 divisors (see below), whose sum is σ = 3500435520. Its totient is φ = 1312662960.

The previous prime is 2165894179. The next prime is 2165894191. The reversal of 2165894181 is 1814985612.

It is a happy number.

2165894181 is a `hidden beast` number, since 21 + 6 + 589 + 41 + 8 + 1 = 666.

It is not a de Polignac number, because 2165894181 - 2¹ = 2165894179 is a prime.

It is a super-2 number, since 2×2165894181² = 9382195206579321522, which contains 22 as substring.

It is an alternating number because its digits alternate between even and odd.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2165894141) 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, 3645990 + ... + 3646583.

It is an arithmetic number, because the mean of its divisors is an integer number (218777220).

Almost surely, 2^2165894181 is an apocalyptic number.

It is an amenable number.

2165894181 is a deficient number, since it is larger than the sum of its proper divisors (1334541339).

2165894181 is a wasteful number, since it uses less digits than its factorization.

2165894181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7292593 (or 7292587 counting only the distinct ones).

The product of its digits is 138240, while the sum is 45.

The square root of 2165894181 is about 46539.1682456831. The cubic root of 2165894181 is about 1293.8355450261.

The spelling of 2165894181 in words is "two billion, one hundred sixty-five million, eight hundred ninety-four thousand, one hundred eighty-one".