640633 has 8 divisors (see below), whose sum is σ = 743040. Its totient is φ = 540960.

The previous prime is 640631. The next prime is 640649. The reversal of 640633 is 336046.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 640633 - 2¹ = 640631 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640631) 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 in 7 ways as a sum of consecutive naturals, for example, 148 + ... + 1141.

It is an arithmetic number, because the mean of its divisors is an integer number (92880).

2⁶⁴⁰⁶³³ is an apocalyptic number.

It is an amenable number.

640633 is a deficient number, since it is larger than the sum of its proper divisors (102407).

640633 is a wasteful number, since it uses less digits than its factorization.

640633 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1367.

The product of its (nonzero) digits is 1296, while the sum is 22.

The square root of 640633 is about 800.3955272239. The cubic root of 640633 is about 86.2057898469.

Adding to 640633 its reverse (336046), we get a palindrome (976679).

The spelling of 640633 in words is "six hundred forty thousand, six hundred thirty-three".