640200221 has 2 divisors, whose sum is σ = 640200222. Its totient is φ = 640200220.

The previous prime is 640200181. The next prime is 640200271. The reversal of 640200221 is 122002046.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 384552100 + 255648121 = 19610^2 + 15989^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640200221 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 640200221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (640200271) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320100110 + 320100111.

It is an arithmetic number, because the mean of its divisors is an integer number (320100111).

Almost surely, 2^640200221 is an apocalyptic number.

It is an amenable number.

640200221 is a deficient number, since it is larger than the sum of its proper divisors (1).

640200221 is an equidigital number, since it uses as much as digits as its factorization.

640200221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 640200221 is about 25302.1781868676. The cubic root of 640200221 is about 861.8637339487.

Adding to 640200221 its reverse (122002046), we get a palindrome (762202267).

The spelling of 640200221 in words is "six hundred forty million, two hundred thousand, two hundred twenty-one".