640750 has 32 divisors (see below), whose sum is σ = 1314144. Its totient is φ = 232000.

The previous prime is 640741. The next prime is 640771. The reversal of 640750 is 57046.

640750 is nontrivially palindromic in base 7.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is an Ulam number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2634 + ... + 2866.

It is an arithmetic number, because the mean of its divisors is an integer number (41067).

2⁶⁴⁰⁷⁵⁰ is an apocalyptic number.

640750 is an abundant number, since it is smaller than the sum of its proper divisors (673394).

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

640750 is a wasteful number, since it uses less digits than its factorization.

640750 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 261 (or 251 counting only the distinct ones).

The product of its (nonzero) digits is 840, while the sum is 22.

The square root of 640750 is about 800.4686127513. The cubic root of 640750 is about 86.2110375022.

Adding to 640750 its reverse (57046), we get a palindrome (697796).

The spelling of 640750 in words is "six hundred forty thousand, seven hundred fifty".