665420 has 48 divisors (see below), whose sum is σ = 1646400. Its totient is φ = 225792.

The previous prime is 665419. The next prime is 665429. The reversal of 665420 is 24566.

It is a nialpdrome in base 7 and base 10.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 665420.

It is not an unprimeable number, because it can be changed into a prime (665429) 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, 6812 + ... + 6908.

It is an arithmetic number, because the mean of its divisors is an integer number (34300).

2⁶⁶⁵⁴²⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 665420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (823200).

665420 is an abundant number, since it is smaller than the sum of its proper divisors (980980).

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

665420 is a wasteful number, since it uses less digits than its factorization.

665420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 127 (or 111 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 665420 is about 815.7327993896. The cubic root of 665420 is about 87.3035593135.

Adding to 665420 its reverse (24566), we get a palindrome (689986).

The spelling of 665420 in words is "six hundred sixty-five thousand, four hundred twenty".