1781222018 has 4 divisors (see below), whose sum is σ = 2671833030. Its totient is φ = 890611008.

The previous prime is 1781222017. The next prime is 1781222041. The reversal of 1781222018 is 8102221871.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8102221871 = 71 ⋅114115801.

It can be written as a sum of positive squares in only one way, i.e., 1780586809 + 635209 = 42197^2 + 797^2 .

It is not an unprimeable number, because it can be changed into a prime (1781222017) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 445305503 + ... + 445305506.

Almost surely, 2^1781222018 is an apocalyptic number.

1781222018 is a deficient number, since it is larger than the sum of its proper divisors (890611012).

1781222018 is an equidigital number, since it uses as much as digits as its factorization.

1781222018 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 890611011.

The product of its (nonzero) digits is 3584, while the sum is 32.

The square root of 1781222018 is about 42204.5260369075. The cubic root of 1781222018 is about 1212.1955488556.

Adding to 1781222018 its reverse (8102221871), we get a palindrome (9883443889).

The spelling of 1781222018 in words is "one billion, seven hundred eighty-one million, two hundred twenty-two thousand, eighteen".