640013 has 8 divisors (see below), whose sum is σ = 707616. Its totient is φ = 574000.

The previous prime is 640009. The next prime is 640019. The reversal of 640013 is 310046.

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

It is a cyclic number.

It is not a de Polignac number, because 640013 - 2² = 640009 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 640013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640019) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 563 + ... + 1263.

It is an arithmetic number, because the mean of its divisors is an integer number (88452).

2⁶⁴⁰⁰¹³ is an apocalyptic number.

It is an amenable number.

640013 is a deficient number, since it is larger than the sum of its proper divisors (67603).

640013 is a wasteful number, since it uses less digits than its factorization.

640013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 795.

The product of its (nonzero) digits is 72, while the sum is 14.

The square root of 640013 is about 800.0081249587. The cubic root of 640013 is about 86.1779710901.

Adding to 640013 its reverse (310046), we get a palindrome (950059).

The spelling of 640013 in words is "six hundred forty thousand, thirteen".