19821399 has 16 divisors (see below), whose sum is σ = 28557312. Its totient is φ = 12156768.

The previous prime is 19821383. The next prime is 19821419. The reversal of 19821399 is 99312891.

It is not a de Polignac number, because 19821399 - 2⁴ = 19821383 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19821399.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19821349) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14274 + ... + 15600.

It is an arithmetic number, because the mean of its divisors is an integer number (1784832).

Almost surely, 2^19821399 is an apocalyptic number.

19821399 is a deficient number, since it is larger than the sum of its proper divisors (8735913).

19821399 is a wasteful number, since it uses less digits than its factorization.

19821399 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1726.

The product of its digits is 34992, while the sum is 42.

The square root of 19821399 is about 4452.1229767382. The cubic root of 19821399 is about 270.6313483391.

The spelling of 19821399 in words is "nineteen million, eight hundred twenty-one thousand, three hundred ninety-nine".