840640219 has 2 divisors, whose sum is σ = 840640220. Its totient is φ = 840640218.

The previous prime is 840640211. The next prime is 840640249. The reversal of 840640219 is 912046048.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 840640219 - 2³ = 840640211 is a prime.

It is a super-2 number, since 2×840640219² = 1413351955600735922, which contains 22 as substring.

It is equal to p_43126585 and since 840640219 and 43126585 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (840640211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420320109 + 420320110.

It is an arithmetic number, because the mean of its divisors is an integer number (420320110).

Almost surely, 2^840640219 is an apocalyptic number.

840640219 is a deficient number, since it is larger than the sum of its proper divisors (1).

840640219 is an equidigital number, since it uses as much as digits as its factorization.

840640219 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13824, while the sum is 34.

The square root of 840640219 is about 28993.7962157424. The cubic root of 840640219 is about 943.7784460879.

The spelling of 840640219 in words is "eight hundred forty million, six hundred forty thousand, two hundred nineteen".