20355 has 16 divisors (see below), whose sum is σ = 34560.
Its totient is φ = 10208.
The previous prime is 20353. The next prime is 20357. The reversal of 20355 is 55302.
Adding to 20355 its reverse (55302), we get a palindrome (75657).
20355 = 182 + 192 + ... + 402.
It is an interprime number because it is at equal distance from previous prime (20353) and next prime (20357).
It is a cyclic number.
It is not a de Polignac number, because 20355 - 21 = 20353 is a prime.
It is a Harshad number since it is a multiple of its sum of digits (15).
It is a d-powerful number, because it can be written as 212 + 0 + 32 + 54 + 56 .
20355 is a Rhonda number in base 16.
20355 is a lucky number.
It is a nialpdrome in base 12.
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 20355.
It is not an unprimeable number, because it can be changed into a prime (20353) 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, 316 + ... + 374.
It is an arithmetic number, because the mean of its divisors is an integer number (2160).
220355 is an apocalyptic number.
20355 is a deficient number, since it is larger than the sum of its proper divisors (14205).
20355 is a wasteful number, since it uses less digits than its factorization.
20355 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 90.
The product of its (nonzero) digits is 150, while the sum is 15.
The square root of 20355 is about 142.6709500915.
The cubic root of 20355 is about 27.3038382345.
The spelling of 20355 in words is "twenty thousand, three hundred fifty-five".