13821520 has 40 divisors (see below), whose sum is σ = 32334984. Its totient is φ = 5494272.

The previous prime is 13821503. The next prime is 13821523. The reversal of 13821520 is 2512831.

It can be written as a sum of positive squares in 4 ways, for example, as 7551504 + 6270016 = 2748^2 + 2504^2 .

It is a tau number, because it is divible by the number of its divisors (40).

It is a super-2 number, since 2×13821520² = 382068830220800, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 13821491 and 13821500.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13821523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 15322 + ... + 16198.

Almost surely, 2^13821520 is an apocalyptic number.

13821520 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

13821520 is an abundant number, since it is smaller than the sum of its proper divisors (18513464).

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

13821520 is a wasteful number, since it uses less digits than its factorization.

13821520 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1087 (or 1081 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 13821520 is about 3717.7304905009. The cubic root of 13821520 is about 239.9856472898.

It can be divided in two parts, 13821 and 520, that added together give a palindrome (14341).

The spelling of 13821520 in words is "thirteen million, eight hundred twenty-one thousand, five hundred twenty".