13821816 has 64 divisors (see below), whose sum is σ = 38534400. Its totient is φ = 4105728.

The previous prime is 13821811. The next prime is 13821823. The reversal of 13821816 is 61812831.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13821811) 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, 6861 + ... + 8643.

It is an arithmetic number, because the mean of its divisors is an integer number (602100).

Almost surely, 2^13821816 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 13821816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (19267200).

13821816 is an abundant number, since it is smaller than the sum of its proper divisors (24712584).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

13821816 is a wasteful number, since it uses less digits than its factorization.

13821816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1828 (or 1824 counting only the distinct ones).

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

The square root of 13821816 is about 3717.7702995209. The cubic root of 13821816 is about 239.9873604455.

The spelling of 13821816 in words is "thirteen million, eight hundred twenty-one thousand, eight hundred sixteen".