640712 has 12 divisors (see below), whose sum is σ = 1205595. Its totient is φ = 319224.

The previous prime is 640691. The next prime is 640727. The reversal of 640712 is 217046.

It is a powerful number, because all its prime factors have an exponent greater than 1 and also an Achilles number because it is not a perfect power.

It can be written as a sum of positive squares in only one way, i.e., 320356 + 320356 = 566^2 + 566^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=566.

It is a Duffinian number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 640712.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2123 + ... + 2405.

2⁶⁴⁰⁷¹² is an apocalyptic number.

It is an amenable number.

640712 is a deficient number, since it is larger than the sum of its proper divisors (564883).

640712 is an equidigital number, since it uses as much as digits as its factorization.

640712 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 572 (or 285 counting only the distinct ones).

The product of its (nonzero) digits is 336, while the sum is 20.

The square root of 640712 is about 800.4448763032. Note that the first 3 decimals coincide. The cubic root of 640712 is about 86.2093332056.

Adding to 640712 its reverse (217046), we get a palindrome (857758).

The spelling of 640712 in words is "six hundred forty thousand, seven hundred twelve".