640594121 has 2 divisors, whose sum is σ = 640594122. Its totient is φ = 640594120.

The previous prime is 640594109. The next prime is 640594151. The reversal of 640594121 is 121495046.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 358723600 + 281870521 = 18940^2 + 16789^2 .

It is a cyclic number.

It is not a de Polignac number, because 640594121 - 2¹⁴ = 640577737 is a prime.

It is not a weakly prime, because it can be changed into another prime (640594151) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320297060 + 320297061.

It is an arithmetic number, because the mean of its divisors is an integer number (320297061).

Almost surely, 2^640594121 is an apocalyptic number.

It is an amenable number.

640594121 is a deficient number, since it is larger than the sum of its proper divisors (1).

640594121 is an equidigital number, since it uses as much as digits as its factorization.

640594121 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 640594121 is about 25309.9609047505. The cubic root of 640594121 is about 862.0404591414.

The spelling of 640594121 in words is "six hundred forty million, five hundred ninety-four thousand, one hundred twenty-one".