1722218 has 4 divisors (see below), whose sum is σ = 2583330. Its totient is φ = 861108.

The previous prime is 1722211. The next prime is 1722241. The reversal of 1722218 is 8122271.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 8122271 = 103 ⋅78857.

It can be written as a sum of positive squares in only one way, i.e., 1054729 + 667489 = 1027^2 + 817^2 .

It is a junction number, because it is equal to n+sod(n) for n = 1722193 and 1722202.

It is not an unprimeable number, because it can be changed into a prime (1722211) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 430553 + ... + 430556.

2^1722218 is an apocalyptic number.

1722218 is a deficient number, since it is larger than the sum of its proper divisors (861112).

1722218 is an equidigital number, since it uses as much as digits as its factorization.

1722218 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 861111.

The product of its digits is 448, while the sum is 23.

The square root of 1722218 is about 1312.3330369994. Note that the first 3 decimals coincide. The cubic root of 1722218 is about 119.8660078473.

Adding to 1722218 its reverse (8122271), we get a palindrome (9844489).

The spelling of 1722218 in words is "one million, seven hundred twenty-two thousand, two hundred eighteen".