635820 has 24 divisors (see below), whose sum is σ = 1780464. Its totient is φ = 169536.

The previous prime is 635813. The next prime is 635821. The reversal of 635820 is 28536.

It is not an unprimeable number, because it can be changed into a prime (635821) by changing a digit.

635820 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 (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5239 + ... + 5358.

It is an arithmetic number, because the mean of its divisors is an integer number (74186).

2⁶³⁵⁸²⁰ is an apocalyptic number.

635820 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

635820 is an abundant number, since it is smaller than the sum of its proper divisors (1144644).

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

635820 is a wasteful number, since it uses less digits than its factorization.

635820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10609 (or 10607 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 24.

The square root of 635820 is about 797.3832202900. The cubic root of 635820 is about 85.9893623042.

The spelling of 635820 in words is "six hundred thirty-five thousand, eight hundred twenty".