222221777778 has 810 divisors, whose sum is σ = 708562736343. Its totient is φ = 51839948160.

The previous prime is 222221777749. The next prime is 222221777783. The reversal of 222221777778 is 877777122222.

It can be written as a sum of positive squares in 5 ways, for example, as 125403099129 + 96818678649 = 354123^2 + 311157^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=333333.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 404 ways as a sum of consecutive naturals, for example, 6005993976 + ... + 6005994012.

Almost surely, 2^222221777778 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 222221777778

222221777778 is an abundant number, since it is smaller than the sum of its proper divisors (486340958565).

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

222221777778 is a wasteful number, since it uses less digits than its factorization.

222221777778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 150 (or 73 counting only the distinct ones).

The product of its digits is 4302592, while the sum is 54.

It can be divided in two parts, 222221 and 777778, that added together give a palindrome (999999).

The spelling of 222221777778 in words is "two hundred twenty-two billion, two hundred twenty-one million, seven hundred seventy-seven thousand, seven hundred seventy-eight".