840641447 has 2 divisors, whose sum is σ = 840641448. Its totient is φ = 840641446.

The previous prime is 840641441. The next prime is 840641489. The reversal of 840641447 is 744146048.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 840641447 - 2⁶ = 840641383 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 840641447.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (840641441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420320723 + 420320724.

It is an arithmetic number, because the mean of its divisors is an integer number (420320724).

Almost surely, 2^840641447 is an apocalyptic number.

840641447 is a deficient number, since it is larger than the sum of its proper divisors (1).

840641447 is an equidigital number, since it uses as much as digits as its factorization.

840641447 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 86016, while the sum is 38.

The square root of 840641447 is about 28993.8173926787. The cubic root of 840641447 is about 943.7789056421.

The spelling of 840641447 in words is "eight hundred forty million, six hundred forty-one thousand, four hundred forty-seven".