640850 has 24 divisors (see below), whose sum is σ = 1363008. Its totient is φ = 219600.

The previous prime is 640847. The next prime is 640853. The reversal of 640850 is 58046.

Added to its reverse (58046) it gives a square (698896 = 836²).

640850 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (640847) and next prime (640853).

It is an Ulam number.

It is not an unprimeable number, because it can be changed into a prime (640853) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 566 + ... + 1265.

It is an arithmetic number, because the mean of its divisors is an integer number (56792).

2⁶⁴⁰⁸⁵⁰ is an apocalyptic number.

640850 is an abundant number, since it is smaller than the sum of its proper divisors (722158).

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

640850 is a wasteful number, since it uses less digits than its factorization.

640850 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1850 (or 1845 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 23.

The square root of 640850 is about 800.5310737254. The cubic root of 640850 is about 86.2155221714.

Adding to 640850 its reverse (58046), we get a palindrome (698896).

It can be divided in two parts, 6408 and 50, that multiplied together give a triangular number (320400 = T₈₀₀).

The spelling of 640850 in words is "six hundred forty thousand, eight hundred fifty".