640199 has 4 divisors (see below), whose sum is σ = 731664. Its totient is φ = 548736.

The previous prime is 640193. The next prime is 640219. The reversal of 640199 is 991046.

640199 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640199 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (640193) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45722 + ... + 45735.

It is an arithmetic number, because the mean of its divisors is an integer number (182916).

2⁶⁴⁰¹⁹⁹ is an apocalyptic number.

640199 is a deficient number, since it is larger than the sum of its proper divisors (91465).

640199 is an equidigital number, since it uses as much as digits as its factorization.

640199 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 91464.

The product of its (nonzero) digits is 1944, while the sum is 29.

The square root of 640199 is about 800.1243653333. The cubic root of 640199 is about 86.1863186028.

The spelling of 640199 in words is "six hundred forty thousand, one hundred ninety-nine".