20908 has 6 divisors (see below), whose sum is σ = 36596. Its totient is φ = 10452.

The previous prime is 20903. The next prime is 20921. The reversal of 20908 is 80902.

It is a plaindrome in base 11.

It is not an unprimeable number, because it can be changed into a prime (20903) 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 as a sum of consecutive naturals, namely, 2610 + ... + 2617.

2²⁰⁹⁰⁸ is an apocalyptic number.

It is an amenable number.

20908 is a deficient number, since it is larger than the sum of its proper divisors (15688).

20908 is a wasteful number, since it uses less digits than its factorization.

20908 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5231 (or 5229 counting only the distinct ones).

The product of its (nonzero) digits is 144, while the sum is 19.

The square root of 20908 is about 144.5959888794. The cubic root of 20908 is about 27.5488937339.

The spelling of 20908 in words is "twenty thousand, nine hundred eight".