20910 has 32 divisors (see below), whose sum is σ = 54432. Its totient is φ = 5120.

The previous prime is 20903. The next prime is 20921. The reversal of 20910 is 1902.

It is a happy number.

20910 is nontrivially palindromic in base 9.

20910 is an esthetic number in base 14, because in such base its adjacent digits differ by 1.

20910 is a nontrivial binomial coefficient, being equal to C(205, 2).

It is an Ulam number.

20910 is an undulating number in base 13.

It is a plaindrome in base 11.

It is a congruent number.

It is an unprimeable number.

20910 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 490 + ... + 530.

It is an arithmetic number, because the mean of its divisors is an integer number (1701).

2²⁰⁹¹⁰ is an apocalyptic number.

20910 is the 204-th triangular number.

It is a practical number, because each smaller number is the sum of distinct divisors of 20910, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27216).

20910 is an abundant number, since it is smaller than the sum of its proper divisors (33522).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20910 is a wasteful number, since it uses less digits than its factorization.

20910 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68.

The product of its (nonzero) digits is 18, while the sum is 12.

The square root of 20910 is about 144.6029045351. The cubic root of 20910 is about 27.5497721223.

The spelling of 20910 in words is "twenty thousand, nine hundred ten".