1645222 has 4 divisors (see below), whose sum is σ = 2467836. Its totient is φ = 822610.

The previous prime is 1645211. The next prime is 1645249. The reversal of 1645222 is 2225461.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 2225461 = 7 ⋅317923.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 1645193 and 1645202.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 411304 + ... + 411307.

It is an arithmetic number, because the mean of its divisors is an integer number (616959).

2^1645222 is an apocalyptic number.

1645222 is a deficient number, since it is larger than the sum of its proper divisors (822614).

1645222 is an equidigital number, since it uses as much as digits as its factorization.

1645222 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 822613.

The product of its digits is 960, while the sum is 22.

The square root of 1645222 is about 1282.6620755289. The cubic root of 1645222 is about 118.0524041871.

The spelling of 1645222 in words is "one million, six hundred forty-five thousand, two hundred twenty-two".