640306211 has 2 divisors, whose sum is σ = 640306212. Its totient is φ = 640306210.

The previous prime is 640306189. The next prime is 640306229. The reversal of 640306211 is 112603046.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640306211 is a prime.

It is not a weakly prime, because it can be changed into another prime (640306811) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320153105 + 320153106.

It is an arithmetic number, because the mean of its divisors is an integer number (320153106).

Almost surely, 2^640306211 is an apocalyptic number.

640306211 is a deficient number, since it is larger than the sum of its proper divisors (1).

640306211 is an equidigital number, since it uses as much as digits as its factorization.

640306211 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 23.

The square root of 640306211 is about 25304.2725838938. The cubic root of 640306211 is about 861.9112940158.

Adding to 640306211 its reverse (112603046), we get a palindrome (752909257).

The spelling of 640306211 in words is "six hundred forty million, three hundred six thousand, two hundred eleven".