20512 has 12 divisors (see below), whose sum is σ = 40446. Its totient is φ = 10240.

The previous prime is 20509. The next prime is 20521. The reversal of 20512 is 21502.

It can be written as a sum of positive squares in only one way, i.e., 13456 + 7056 = 116^2 + 84^2 .

It is a plaindrome in base 11.

It is a nialpdrome in base 12.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (3) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 289 + ... + 352.

2²⁰⁵¹² is an apocalyptic number.

It is an amenable number.

20512 is a deficient number, since it is larger than the sum of its proper divisors (19934).

20512 is an equidigital number, since it uses as much as digits as its factorization.

20512 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 651 (or 643 counting only the distinct ones).

The product of its (nonzero) digits is 20, while the sum is 10.

The square root of 20512 is about 143.2201103197. The cubic root of 20512 is about 27.3738575310.

Subtracting from 20512 its sum of digits (10), we obtain a palindrome (20502).

Multiplying 20512 by its sum of digits (10), we get a triangular number (205120 = T₆₄₀).

Subtracting 20512 from its reverse (21502), we obtain a triangular number (990 = T₄₄).

The spelling of 20512 in words is "twenty thousand, five hundred twelve".