640526 has 8 divisors (see below), whose sum is σ = 1017360. Its totient is φ = 301408.

The previous prime is 640499. The next prime is 640529. The reversal of 640526 is 625046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640529) by changing a digit.

640526 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 3 ways as a sum of consecutive naturals, for example, 9386 + ... + 9453.

It is an arithmetic number, because the mean of its divisors is an integer number (127170).

2⁶⁴⁰⁵²⁶ is an apocalyptic number.

640526 is a deficient number, since it is larger than the sum of its proper divisors (376834).

640526 is a wasteful number, since it uses less digits than its factorization.

640526 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18858.

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 640526 is about 800.3286824799. The cubic root of 640526 is about 86.2009901498.

The spelling of 640526 in words is "six hundred forty thousand, five hundred twenty-six".