840642659 has 2 divisors, whose sum is σ = 840642660. Its totient is φ = 840642658.

The previous prime is 840642629. The next prime is 840642731. The reversal of 840642659 is 956246048.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 840642659 - 2¹⁶ = 840577123 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (840642619) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420321329 + 420321330.

It is an arithmetic number, because the mean of its divisors is an integer number (420321330).

Almost surely, 2^840642659 is an apocalyptic number.

840642659 is a deficient number, since it is larger than the sum of its proper divisors (1).

840642659 is an equidigital number, since it uses as much as digits as its factorization.

840642659 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 414720, while the sum is 44.

The square root of 840642659 is about 28993.8382936789. The cubic root of 840642659 is about 943.7793592083.

The spelling of 840642659 in words is "eight hundred forty million, six hundred forty-two thousand, six hundred fifty-nine".