20499 has 4 divisors (see below), whose sum is σ = 27336. Its totient is φ = 13664.

The previous prime is 20483. The next prime is 20507. The reversal of 20499 is 99402.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20499 - 2⁴ = 20483 is a prime.

It is an Ulam number.

It is a D-number.

It is a plaindrome in base 5 and base 11.

It is a nialpdrome in base 12.

It is not an unprimeable number, because it can be changed into a prime (20479) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3414 + ... + 3419.

It is an arithmetic number, because the mean of its divisors is an integer number (6834).

2²⁰⁴⁹⁹ is an apocalyptic number.

20499 is a deficient number, since it is larger than the sum of its proper divisors (6837).

20499 is an equidigital number, since it uses as much as digits as its factorization.

20499 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6836.

The product of its (nonzero) digits is 648, while the sum is 24.

The square root of 20499 is about 143.1747184387. The cubic root of 20499 is about 27.3680733502.

It can be divided in two parts, 204 and 99, that added together give a palindrome (303).

The spelling of 20499 in words is "twenty thousand, four hundred ninety-nine".