640120 has 32 divisors (see below), whose sum is σ = 1552320. Its totient is φ = 236160.

The previous prime is 640109. The next prime is 640121. The reversal of 640120 is 21046.

It is a super-2 number, since 2×640120² = 819507228800, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (13).

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 640120.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640121) by changing a digit.

640120 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 7 ways as a sum of consecutive naturals, for example, 96 + ... + 1135.

It is an arithmetic number, because the mean of its divisors is an integer number (48510).

2⁶⁴⁰¹²⁰ 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 640120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (776160).

640120 is an abundant number, since it is smaller than the sum of its proper divisors (912200).

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

640120 is a wasteful number, since it uses less digits than its factorization.

640120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1255 (or 1251 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 13.

The square root of 640120 is about 800.0749964847. The cubic root of 640120 is about 86.1827733514.

Adding to 640120 its reverse (21046), we get a palindrome (661166).

The spelling of 640120 in words is "six hundred forty thousand, one hundred twenty".