19821223 has 4 divisors (see below), whose sum is σ = 19839568. Its totient is φ = 19802880.

The previous prime is 19821209. The next prime is 19821251. The reversal of 19821223 is 32212891.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 32212891 = 43 ⋅749137.

It is a cyclic number.

It is not a de Polignac number, because 19821223 - 2⁹ = 19820711 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 19821191 and 19821200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19821203) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7443 + ... + 9748.

It is an arithmetic number, because the mean of its divisors is an integer number (4959892).

Almost surely, 2^19821223 is an apocalyptic number.

19821223 is a deficient number, since it is larger than the sum of its proper divisors (18345).

19821223 is a wasteful number, since it uses less digits than its factorization.

19821223 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18344.

The product of its digits is 1728, while the sum is 28.

The square root of 19821223 is about 4452.1032108432. The cubic root of 19821223 is about 270.6305473317.

The spelling of 19821223 in words is "nineteen million, eight hundred twenty-one thousand, two hundred twenty-three".