640529 has 2 divisors, whose sum is σ = 640530. Its totient is φ = 640528.

The previous prime is 640499. The next prime is 640531. The reversal of 640529 is 925046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 640000 + 529 = 800^2 + 23^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-640529 is a prime.

Together with 640531, it forms a pair of twin primes.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 640498 and 640507.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 640529.

It is not a weakly prime, because it can be changed into another prime (640579) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320264 + 320265.

It is an arithmetic number, because the mean of its divisors is an integer number (320265).

2⁶⁴⁰⁵²⁹ is an apocalyptic number.

It is an amenable number.

640529 is a deficient number, since it is larger than the sum of its proper divisors (1).

640529 is an equidigital number, since it uses as much as digits as its factorization.

640529 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2160, while the sum is 26.

The square root of 640529 is about 800.3305567077. The cubic root of 640529 is about 86.2011247280.

It can be divided in two parts, 6405 and 29, that multiplied together give a triangular number (185745 = T₆₀₉).

The spelling of 640529 in words is "six hundred forty thousand, five hundred twenty-nine".