640051 has 8 divisors (see below), whose sum is σ = 668304. Its totient is φ = 612480.

The previous prime is 640049. The next prime is 640061. The reversal of 640051 is 150046.

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 640051 - 2¹ = 640049 is a prime.

It is a Duffinian number.

640051 is a lucky number.

It is not an unprimeable number, because it can be changed into a prime (640061) 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, 2631 + ... + 2863.

It is an arithmetic number, because the mean of its divisors is an integer number (83538).

2⁶⁴⁰⁰⁵¹ is an apocalyptic number.

640051 is a deficient number, since it is larger than the sum of its proper divisors (28253).

640051 is a wasteful number, since it uses less digits than its factorization.

640051 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 341.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 640051 is about 800.0318743650. The cubic root of 640051 is about 86.1796766273.

Adding to 640051 its reverse (150046), we get a palindrome (790097).

The spelling of 640051 in words is "six hundred forty thousand, fifty-one".