640430 has 24 divisors (see below), whose sum is σ = 1342008. Its totient is φ = 219408.

The previous prime is 640421. The next prime is 640457. The reversal of 640430 is 34046.

It is a junction number, because it is equal to n+sod(n) for n = 640399 and 640408.

It is a congruent number.

It is an unprimeable number.

640430 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 164 + ... + 1143.

It is an arithmetic number, because the mean of its divisors is an integer number (55917).

2⁶⁴⁰⁴³⁰ is an apocalyptic number.

640430 is an abundant number, since it is smaller than the sum of its proper divisors (701578).

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

640430 is a wasteful number, since it uses less digits than its factorization.

640430 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1328 (or 1321 counting only the distinct ones).

The product of its (nonzero) digits is 288, while the sum is 17.

The square root of 640430 is about 800.2687048736. The cubic root of 640430 is about 86.1966834246.

Adding to 640430 its reverse (34046), we get a palindrome (674476).

The spelling of 640430 in words is "six hundred forty thousand, four hundred thirty".