1816558216 has 128 divisors (see below), whose sum is σ = 4034396160. Its totient is φ = 758419200.

The previous prime is 1816558189. The next prime is 1816558277. The reversal of 1816558216 is 6128556181.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9510681 + ... + 9510871.

It is an arithmetic number, because the mean of its divisors is an integer number (31518720).

Almost surely, 2^1816558216 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1816558216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2017198080).

1816558216 is an abundant number, since it is smaller than the sum of its proper divisors (2217837944).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1816558216 is a wasteful number, since it uses less digits than its factorization.

1816558216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 395 (or 391 counting only the distinct ones).

The product of its digits is 115200, while the sum is 43.

The square root of 1816558216 is about 42621.1005958316. The cubic root of 1816558216 is about 1220.1590350772.

The spelling of 1816558216 in words is "one billion, eight hundred sixteen million, five hundred fifty-eight thousand, two hundred sixteen".