1991222 has 4 divisors (see below), whose sum is σ = 2986836. Its totient is φ = 995610.

The previous prime is 1991189. The next prime is 1991239. The reversal of 1991222 is 2221991.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a junction number, because it is equal to n+sod(n) for n = 1991191 and 1991200.

It is a congruent number.

It is an unprimeable number.

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, 497804 + ... + 497807.

It is an arithmetic number, because the mean of its divisors is an integer number (746709).

2^1991222 is an apocalyptic number.

1991222 is a deficient number, since it is larger than the sum of its proper divisors (995614).

1991222 is an equidigital number, since it uses as much as digits as its factorization.

1991222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 995613.

The product of its digits is 648, while the sum is 26.

The square root of 1991222 is about 1411.1066579107. The cubic root of 1991222 is about 125.8075082108.

The spelling of 1991222 in words is "one million, nine hundred ninety-one thousand, two hundred twenty-two".