19991222 has 4 divisors (see below), whose sum is σ = 29986836. Its totient is φ = 9995610.

The previous prime is 19991219. The next prime is 19991227. The reversal of 19991222 is 22219991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 22219991 = 41 ⋅541951.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19991227) 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, 4997804 + ... + 4997807.

It is an arithmetic number, because the mean of its divisors is an integer number (7496709).

Almost surely, 2^19991222 is an apocalyptic number.

19991222 is a deficient number, since it is larger than the sum of its proper divisors (9995614).

19991222 is an equidigital number, since it uses as much as digits as its factorization.

19991222 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9995613.

The product of its digits is 5832, while the sum is 35.

The square root of 19991222 is about 4471.1544370554. The cubic root of 19991222 is about 271.4020439185.

The spelling of 19991222 in words is "nineteen million, nine hundred ninety-one thousand, two hundred twenty-two".