640784201 has 2 divisors, whose sum is σ = 640784202. Its totient is φ = 640784200.

The previous prime is 640784189. The next prime is 640784227. The reversal of 640784201 is 102487046.

640784201 = 17899² + 17900².

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 320410000 + 320374201 = 17900^2 + 17899^2 .

It is a cyclic number.

It is not a de Polignac number, because 640784201 - 2¹⁴ = 640767817 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (640784401) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320392100 + 320392101.

It is an arithmetic number, because the mean of its divisors is an integer number (320392101).

Almost surely, 2^640784201 is an apocalyptic number.

640784201 is the 17900-th centered square number.

It is an amenable number.

640784201 is a deficient number, since it is larger than the sum of its proper divisors (1).

640784201 is an equidigital number, since it uses as much as digits as its factorization.

640784201 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10752, while the sum is 32.

The square root of 640784201 is about 25313.7156695733. The cubic root of 640784201 is about 862.1257135644.

The spelling of 640784201 in words is "six hundred forty million, seven hundred eighty-four thousand, two hundred one".