20163521 has 4 divisors (see below), whose sum is σ = 23044032. Its totient is φ = 17283012.

The previous prime is 20163509. The next prime is 20163529. The reversal of 20163521 is 12536102.

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 a cyclic number.

It is not a de Polignac number, because 20163521 - 2⁶ = 20163457 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20163493 and 20163502.

It is not an unprimeable number, because it can be changed into a prime (20163529) 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, 1440245 + ... + 1440258.

It is an arithmetic number, because the mean of its divisors is an integer number (5761008).

Almost surely, 2^20163521 is an apocalyptic number.

It is an amenable number.

20163521 is a deficient number, since it is larger than the sum of its proper divisors (2880511).

20163521 is an equidigital number, since it uses as much as digits as its factorization.

20163521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2880510.

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 20163521 is about 4490.3809415238. The cubic root of 20163521 is about 272.1795284303.

Adding to 20163521 its reverse (12536102), we get a palindrome (32699623).

The spelling of 20163521 in words is "twenty million, one hundred sixty-three thousand, five hundred twenty-one".