20155 has 8 divisors (see below), whose sum is σ = 25200. Its totient is φ = 15456.

The previous prime is 20149. The next prime is 20161. The reversal of 20155 is 55102.

20155 = 11² + 12² + ... + 39².

It is an interprime number because it is at equal distance from previous prime (20149) and next prime (20161).

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20155 - 2³ = 20147 is a prime.

It is an Ulam number.

20155 is an undulating number in base 12.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 76 + ... + 214.

It is an arithmetic number, because the mean of its divisors is an integer number (3150).

2²⁰¹⁵⁵ is an apocalyptic number.

20155 is a deficient number, since it is larger than the sum of its proper divisors (5045).

20155 is a wasteful number, since it uses less digits than its factorization.

20155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 173.

The product of its (nonzero) digits is 50, while the sum is 13.

The square root of 20155 is about 141.9683063222. The cubic root of 20155 is about 27.2141182473.

Adding to 20155 its reverse (55102), we get a palindrome (75257).

It can be divided in two parts, 201 and 55, that added together give a 8-th power (256 = 2⁸).

The spelling of 20155 in words is "twenty thousand, one hundred fifty-five".