640732 has 6 divisors (see below), whose sum is σ = 1121288. Its totient is φ = 320364.

The previous prime is 640727. The next prime is 640733. The reversal of 640732 is 237046.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640733) by changing a digit.

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 as a sum of consecutive naturals, namely, 80088 + ... + 80095.

2⁶⁴⁰⁷³² is an apocalyptic number.

It is an amenable number.

640732 is a deficient number, since it is larger than the sum of its proper divisors (480556).

640732 is a wasteful number, since it uses less digits than its factorization.

640732 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160187 (or 160185 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 22.

The square root of 640732 is about 800.4573692584. The cubic root of 640732 is about 86.2102302122.

Adding to 640732 its reverse (237046), we get a palindrome (877778).

The spelling of 640732 in words is "six hundred forty thousand, seven hundred thirty-two".