2161973218 has 8 divisors (see below), whose sum is σ = 3246970860. Its totient is φ = 1079649600.

The previous prime is 2161973161. The next prime is 2161973267. The reversal of 2161973218 is 8123791612.

It can be written as a sum of positive squares in 2 ways, for example, as 2161971009 + 2209 = 46497^2 + 47^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 666483 + ... + 669718.

Almost surely, 2^2161973218 is an apocalyptic number.

2161973218 is a deficient number, since it is larger than the sum of its proper divisors (1084997642).

2161973218 is a wasteful number, since it uses less digits than its factorization.

2161973218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1337012.

The product of its digits is 36288, while the sum is 40.

The square root of 2161973218 is about 46497.0237542146. The cubic root of 2161973218 is about 1293.0543210050.

The spelling of 2161973218 in words is "two billion, one hundred sixty-one million, nine hundred seventy-three thousand, two hundred eighteen".