840878239 has 2 divisors, whose sum is σ = 840878240. Its totient is φ = 840878238.

The previous prime is 840878237. The next prime is 840878249. The reversal of 840878239 is 932878048.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 840878239 - 2¹ = 840878237 is a prime.

It is a super-2 number, since 2×840878239² = 1414152425647482242, which contains 22 as substring.

Together with 840878237, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 840878192 and 840878201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (840878237) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420439119 + 420439120.

It is an arithmetic number, because the mean of its divisors is an integer number (420439120).

Almost surely, 2^840878239 is an apocalyptic number.

840878239 is a deficient number, since it is larger than the sum of its proper divisors (1).

840878239 is an equidigital number, since it uses as much as digits as its factorization.

840878239 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 774144, while the sum is 49.

The square root of 840878239 is about 28997.9005964225. The cubic root of 840878239 is about 943.8675119144.

The spelling of 840878239 in words is "eight hundred forty million, eight hundred seventy-eight thousand, two hundred thirty-nine".