20115 has 16 divisors (see below), whose sum is σ = 36000.
Its totient is φ = 10656.
The previous prime is 20113. The next prime is 20117. The reversal of 20115 is 51102.
It is a happy number.
20115 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.
It is an interprime number because it is at equal distance from previous prime (20113) and next prime (20117).
It is not a de Polignac number, because 20115 - 21 = 20113 is a prime.
It is a super-2 number, since 2×201152 = 809226450, which contains 22 as substring.
It is a Harshad number since it is a multiple of its sum of digits (9).
It is a junction number, because it is equal to n+sod(n) for n = 20097 and 20106.
It is not an unprimeable number, because it can be changed into a prime (20113) by changing a digit.
It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 61 + ... + 209.
It is an arithmetic number, because the mean of its divisors is an integer number (2250).
220115 is an apocalyptic number.
20115 is the 90-th heptagonal number.
20115 is a deficient number, since it is larger than the sum of its proper divisors (15885).
20115 is a wasteful number, since it uses less digits than its factorization.
20115 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 163 (or 157 counting only the distinct ones).
The product of its (nonzero) digits is 10, while the sum is 9.
The square root of 20115 is about 141.8273598429.
The cubic root of 20115 is about 27.1961031038.
Adding to 20115 its reverse (51102), we get a palindrome (71217).
It can be divided in two parts, 2011 and 5, that added together give a triangular number (2016 = T63).
The spelling of 20115 in words is "twenty thousand, one hundred fifteen".