66420 has 60 divisors (see below), whose sum is σ = 213444. Its totient is φ = 17280.

The previous prime is 66413. The next prime is 66431. The reversal of 66420 is 2466.

66420 is a `hidden beast` number, since 664 + 2 + 0 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 11664 + 54756 = 108^2 + 234^2 .

It is a tau number, because it is divible by the number of its divisors (60).

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a nialpdrome in base 9 and base 10.

It is a zygodrome in base 9.

It is a junction number, because it is equal to n+sod(n) for n = 66393 and 66402.

It is a congruent number.

It is an unprimeable number.

66420 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 (7) of ones.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 1600 + ... + 1640.

2⁶⁶⁴²⁰ is an apocalyptic number.

66420 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (106722).

66420 is an abundant number, since it is smaller than the sum of its proper divisors (147024).

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

66420 is a wasteful number, since it uses less digits than its factorization.

66420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 62 (or 51 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 18.

The square root of 66420 is about 257.7207791390. The cubic root of 66420 is about 40.4979422823.

Adding to 66420 its reverse (2466), we get a palindrome (68886).

The spelling of 66420 in words is "sixty-six thousand, four hundred twenty".