640862 has 4 divisors (see below), whose sum is σ = 961296. Its totient is φ = 320430.

The previous prime is 640859. The next prime is 640873. The reversal of 640862 is 268046.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 160214 + ... + 160217.

It is an arithmetic number, because the mean of its divisors is an integer number (240324).

2⁶⁴⁰⁸⁶² is an apocalyptic number.

640862 is a deficient number, since it is larger than the sum of its proper divisors (320434).

640862 is a wasteful number, since it uses less digits than its factorization.

640862 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 320433.

The product of its (nonzero) digits is 2304, while the sum is 26.

The square root of 640862 is about 800.5385687148. The cubic root of 640862 is about 86.2160603003.

Subtracting from 640862 its reverse (268046), we obtain a triangular number (372816 = T₈₆₃).

The spelling of 640862 in words is "six hundred forty thousand, eight hundred sixty-two".