20323521 has 32 divisors (see below), whose sum is σ = 32016000. Its totient is φ = 12705984.

The previous prime is 20323489. The next prime is 20323529. The reversal of 20323521 is 12532302.

It is not a de Polignac number, because 20323521 - 2⁵ = 20323489 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 20323494 and 20323503.

It is not an unprimeable number, because it can be changed into a prime (20323529) 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 31 ways as a sum of consecutive naturals, for example, 88635 + ... + 88863.

It is an arithmetic number, because the mean of its divisors is an integer number (1000500).

Almost surely, 2^20323521 is an apocalyptic number.

It is an amenable number.

20323521 is a deficient number, since it is larger than the sum of its proper divisors (11692479).

20323521 is a wasteful number, since it uses less digits than its factorization.

20323521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 430 (or 424 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 18.

The square root of 20323521 is about 4508.1615987007. The cubic root of 20323521 is about 272.8975584729.

Adding to 20323521 its reverse (12532302), we get a palindrome (32855823).

The spelling of 20323521 in words is "twenty million, three hundred twenty-three thousand, five hundred twenty-one".