840220439 has 2 divisors, whose sum is σ = 840220440. Its totient is φ = 840220438.

The previous prime is 840220417. The next prime is 840220441. The reversal of 840220439 is 934022048.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-840220439 is a prime.

It is a super-2 number, since 2×840220439² = 1411940772226705442, which contains 22 as substring.

Together with 840220441, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (840280439) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420110219 + 420110220.

It is an arithmetic number, because the mean of its divisors is an integer number (420110220).

Almost surely, 2^840220439 is an apocalyptic number.

840220439 is a deficient number, since it is larger than the sum of its proper divisors (1).

840220439 is an equidigital number, since it uses as much as digits as its factorization.

840220439 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 32.

The square root of 840220439 is about 28986.5561769590. The cubic root of 840220439 is about 943.6213256494.

The spelling of 840220439 in words is "eight hundred forty million, two hundred twenty thousand, four hundred thirty-nine".