640560 has 80 divisors (see below), whose sum is σ = 2115936. Its totient is φ = 159744.

The previous prime is 640531. The next prime is 640579. The reversal of 640560 is 65046.

It is a tau number, because it is divible by the number of its divisors (80).

It is a super-2 number, since 2×640560² = 820634227200, which contains 22 as substring.

It is an unprimeable number.

640560 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, 4002 + ... + 4158.

2⁶⁴⁰⁵⁶⁰ is an apocalyptic number.

640560 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 640560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1057968).

640560 is an abundant number, since it is smaller than the sum of its proper divisors (1475376).

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

640560 is a wasteful number, since it uses less digits than its factorization.

640560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 190 (or 184 counting only the distinct ones).

The product of its (nonzero) digits is 720, while the sum is 21.

The square root of 640560 is about 800.3499234710. The cubic root of 640560 is about 86.2025153452.

The spelling of 640560 in words is "six hundred forty thousand, five hundred sixty".