640443211 has 8 divisors (see below), whose sum is σ = 668542464. Its totient is φ = 612365160.

The previous prime is 640443191. The next prime is 640443301. The reversal of 640443211 is 112344046.

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

It is a cyclic number.

It is not a de Polignac number, because 640443211 - 2²⁹ = 103572299 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (640440211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 110590 + ... + 116236.

It is an arithmetic number, because the mean of its divisors is an integer number (83567808).

Almost surely, 2^640443211 is an apocalyptic number.

640443211 is a deficient number, since it is larger than the sum of its proper divisors (28099253).

640443211 is a wasteful number, since it uses less digits than its factorization.

640443211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10601.

The product of its (nonzero) digits is 2304, while the sum is 25.

The square root of 640443211 is about 25306.9794918319. The cubic root of 640443211 is about 861.9727611830.

Adding to 640443211 its reverse (112344046), we get a palindrome (752787257).

The spelling of 640443211 in words is "six hundred forty million, four hundred forty-three thousand, two hundred eleven".