640802 has 4 divisors (see below), whose sum is σ = 961206. Its totient is φ = 320400.

The previous prime is 640793. The next prime is 640837. The reversal of 640802 is 208046.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 638401 + 2401 = 799^2 + 49^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160199 + ... + 160202.

2⁶⁴⁰⁸⁰² is an apocalyptic number.

640802 is a deficient number, since it is larger than the sum of its proper divisors (320404).

640802 is a wasteful number, since it uses less digits than its factorization.

640802 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 320403.

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 640802 is about 800.5010930661. The cubic root of 640802 is about 86.2133695884.

Adding to 640802 its reverse (208046), we get a palindrome (848848).

The spelling of 640802 in words is "six hundred forty thousand, eight hundred two".