13816821 has 4 divisors (see below), whose sum is σ = 18422432. Its totient is φ = 9211212.

The previous prime is 13816787. The next prime is 13816823. The reversal of 13816821 is 12861831.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 13816821 - 2⁶ = 13816757 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13816823) 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, 2302801 + ... + 2302806.

It is an arithmetic number, because the mean of its divisors is an integer number (4605608).

Almost surely, 2^13816821 is an apocalyptic number.

It is an amenable number.

13816821 is a deficient number, since it is larger than the sum of its proper divisors (4605611).

13816821 is an equidigital number, since it uses as much as digits as its factorization.

13816821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4605610.

The product of its digits is 2304, while the sum is 30.

The square root of 13816821 is about 3717.0984652010. The cubic root of 13816821 is about 239.9584476674.

The spelling of 13816821 in words is "thirteen million, eight hundred sixteen thousand, eight hundred twenty-one".