2221720370218 has 16 divisors (see below), whose sum is σ = 3351132616104. Its totient is φ = 1104676678080.

The previous prime is 2221720370213. The next prime is 2221720370291. The reversal of 2221720370218 is 8120730271222.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 1407670721209 + 814049649009 = 1186453^2 + 902247^2 .

It is not an unprimeable number, because it can be changed into a prime (2221720370213) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9556696 + ... + 9786412.

Almost surely, 2^{2221720370218} is an apocalyptic number.

2221720370218 is a deficient number, since it is larger than the sum of its proper divisors (1129412245886).

2221720370218 is a wasteful number, since it uses less digits than its factorization.

2221720370218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 256617.

The product of its (nonzero) digits is 37632, while the sum is 37.

The spelling of 2221720370218 in words is "two trillion, two hundred twenty-one billion, seven hundred twenty million, three hundred seventy thousand, two hundred eighteen".