13803521 has 4 divisors (see below), whose sum is σ = 13823700. Its totient is φ = 13783344.

The previous prime is 13803499. The next prime is 13803547. The reversal of 13803521 is 12530831.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 12530831 = 199 ⋅62969.

It can be written as a sum of positive squares in 2 ways, for example, as 3312400 + 10491121 = 1820^2 + 3239^2 .

It is a cyclic number.

It is not a de Polignac number, because 13803521 - 2¹⁸ = 13541377 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13803121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9026 + ... + 10443.

It is an arithmetic number, because the mean of its divisors is an integer number (3455925).

It is a Proth number, since it is equal to 1685 ⋅ 2¹³ + 1 and 1685 < 2¹³.

Almost surely, 2^13803521 is an apocalyptic number.

It is an amenable number.

13803521 is a deficient number, since it is larger than the sum of its proper divisors (20179).

13803521 is an equidigital number, since it uses as much as digits as its factorization.

13803521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20178.

The product of its (nonzero) digits is 720, while the sum is 23.

The square root of 13803521 is about 3715.3090046455. The cubic root of 13803521 is about 239.8814286984.

The spelling of 13803521 in words is "thirteen million, eight hundred three thousand, five hundred twenty-one".