640020659 has 2 divisors, whose sum is σ = 640020660. Its totient is φ = 640020658.

The previous prime is 640020611. The next prime is 640020673. The reversal of 640020659 is 956020046.

640020659 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 640020659 - 2¹² = 640016563 is a prime.

It is not a weakly prime, because it can be changed into another prime (640020559) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 320010329 + 320010330.

It is an arithmetic number, because the mean of its divisors is an integer number (320010330).

Almost surely, 2^640020659 is an apocalyptic number.

640020659 is a deficient number, since it is larger than the sum of its proper divisors (1).

640020659 is an equidigital number, since it uses as much as digits as its factorization.

640020659 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 12960, while the sum is 32.

The square root of 640020659 is about 25298.6295873907. The cubic root of 640020659 is about 861.7831485101.

The spelling of 640020659 in words is "six hundred forty million, twenty thousand, six hundred fifty-nine".