640450 has 12 divisors (see below), whose sum is σ = 1191330. Its totient is φ = 256160.

The previous prime is 640421. The next prime is 640457. The reversal of 640450 is 54046.

640450 is nontrivially palindromic in base 3.

It can be written as a sum of positive squares in 3 ways, for example, as 418609 + 221841 = 647^2 + 471^2 .

It is not an unprimeable number, because it can be changed into a prime (640457) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6355 + ... + 6454.

2⁶⁴⁰⁴⁵⁰ is an apocalyptic number.

640450 is a deficient number, since it is larger than the sum of its proper divisors (550880).

640450 is a wasteful number, since it uses less digits than its factorization.

640450 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12821 (or 12816 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 19.

The square root of 640450 is about 800.2812005789. The cubic root of 640450 is about 86.1975806945.

Adding to 640450 its reverse (54046), we get a palindrome (694496).

The spelling of 640450 in words is "six hundred forty thousand, four hundred fifty".