65820 has 24 divisors (see below), whose sum is σ = 184464. Its totient is φ = 17536.

The previous prime is 65809. The next prime is 65827. The reversal of 65820 is 2856.

It is a happy number.

It is an Ulam number.

It is a nialpdrome in base 12.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (65827) by changing a digit.

65820 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 489 + ... + 608.

It is an arithmetic number, because the mean of its divisors is an integer number (7686).

2⁶⁵⁸²⁰ is an apocalyptic number.

65820 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

65820 is an abundant number, since it is smaller than the sum of its proper divisors (118644).

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

It is a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (92232).

65820 is a wasteful number, since it uses less digits than its factorization.

65820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1109 (or 1107 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 21.

The square root of 65820 is about 256.5540878645. The cubic root of 65820 is about 40.3756282112.

The spelling of 65820 in words is "sixty-five thousand, eight hundred twenty".