13821999 has 4 divisors (see below), whose sum is σ = 18429336. Its totient is φ = 9214664.

The previous prime is 13821971. The next prime is 13822007. The reversal of 13821999 is 99912831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 99912831 = 3 ⋅33304277.

It is a cyclic number.

It is not a de Polignac number, because 13821999 - 2¹¹ = 13819951 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 13821999.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13821959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2303664 + ... + 2303669.

It is an arithmetic number, because the mean of its divisors is an integer number (4607334).

Almost surely, 2^13821999 is an apocalyptic number.

13821999 is a deficient number, since it is larger than the sum of its proper divisors (4607337).

13821999 is an equidigital number, since it uses as much as digits as its factorization.

13821999 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4607336.

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

The square root of 13821999 is about 3717.7949109654. The cubic root of 13821999 is about 239.9884195801.

The spelling of 13821999 in words is "thirteen million, eight hundred twenty-one thousand, nine hundred ninety-nine".