660420 has 48 divisors (see below), whose sum is σ = 2056320. Its totient is φ = 175968.

The previous prime is 660409. The next prime is 660449. The reversal of 660420 is 24066.

660420 is a `hidden beast` number, since 660 + 4 + 2 + 0 = 666.

It is a hoax number, since the sum of its digits (18) coincides with the sum of the digits of its distinct prime factors.

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

It is a junction number, because it is equal to n+sod(n) for n = 660393 and 660402.

It is an unprimeable number.

660420 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 72 + ... + 1151.

It is an arithmetic number, because the mean of its divisors is an integer number (42840).

2⁶⁶⁰⁴²⁰ is an apocalyptic number.

660420 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 660420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1028160).

660420 is an abundant number, since it is smaller than the sum of its proper divisors (1395900).

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

660420 is a wasteful number, since it uses less digits than its factorization.

660420 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1241 (or 1233 counting only the distinct ones).

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

The square root of 660420 is about 812.6622914840. The cubic root of 660420 is about 87.0843415149.

Adding to 660420 its reverse (24066), we get a palindrome (684486).

The spelling of 660420 in words is "six hundred sixty thousand, four hundred twenty".