1798220218 has 4 divisors (see below), whose sum is σ = 2697330330. Its totient is φ = 899110108.

The previous prime is 1798220213. The next prime is 1798220251. The reversal of 1798220218 is 8120228971.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8120228971 = 311 ⋅26110061.

It can be written as a sum of positive squares in only one way, i.e., 1448791969 + 349428249 = 38063^2 + 18693^2 .

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is not an unprimeable number, because it can be changed into a prime (1798220213) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 449555053 + ... + 449555056.

Almost surely, 2^1798220218 is an apocalyptic number.

1798220218 is a deficient number, since it is larger than the sum of its proper divisors (899110112).

1798220218 is an equidigital number, since it uses as much as digits as its factorization.

1798220218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 899110111.

The product of its (nonzero) digits is 32256, while the sum is 40.

The square root of 1798220218 is about 42405.4267517732. The cubic root of 1798220218 is about 1216.0393412112.

The spelling of 1798220218 in words is "one billion, seven hundred ninety-eight million, two hundred twenty thousand, two hundred eighteen".