663820 has 12 divisors (see below), whose sum is σ = 1394064. Its totient is φ = 265520.

The previous prime is 663797. The next prime is 663821. The reversal of 663820 is 28366.

It is not an unprimeable number, because it can be changed into a prime (663821) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16576 + ... + 16615.

It is an arithmetic number, because the mean of its divisors is an integer number (116172).

2⁶⁶³⁸²⁰ is an apocalyptic number.

It is an amenable number.

663820 is an abundant number, since it is smaller than the sum of its proper divisors (730244).

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

663820 is a wasteful number, since it uses less digits than its factorization.

663820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33200 (or 33198 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 663820 is about 814.7514958563. The cubic root of 663820 is about 87.2335294564.

The spelling of 663820 in words is "six hundred sixty-three thousand, eight hundred twenty".