20156 has 6 divisors (see below), whose sum is σ = 35280. Its totient is φ = 10076.

The previous prime is 20149. The next prime is 20161. The reversal of 20156 is 65102.

20156 is nontrivially palindromic in base 8.

It is a self number, because there is not a number n which added to its sum of digits gives 20156.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 20156.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2516 + ... + 2523.

It is an arithmetic number, because the mean of its divisors is an integer number (5880).

2²⁰¹⁵⁶ is an apocalyptic number.

It is an amenable number.

20156 is a deficient number, since it is larger than the sum of its proper divisors (15124).

20156 is a wasteful number, since it uses less digits than its factorization.

20156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5043 (or 5041 counting only the distinct ones).

The product of its (nonzero) digits is 60, while the sum is 14.

The square root of 20156 is about 141.9718281914. The cubic root of 20156 is about 27.2145683204.

Adding to 20156 its reverse (65102), we get a palindrome (85258).

It can be divided in two parts, 2015 and 6, that multiplied together give a triangular number (12090 = T₁₅₅).

The spelling of 20156 in words is "twenty thousand, one hundred fifty-six".