840043291 has 2 divisors, whose sum is σ = 840043292. Its totient is φ = 840043290.

The previous prime is 840043289. The next prime is 840043327. The reversal of 840043291 is 192340048.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 840043291 - 2¹ = 840043289 is a prime.

It is a super-2 number, since 2×840043291² = 1411345461508221362, which contains 22 as substring.

Together with 840043289, it forms a pair of twin primes.

It is equal to p_43097512 and since 840043291 and 43097512 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 (840043891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 420021645 + 420021646.

It is an arithmetic number, because the mean of its divisors is an integer number (420021646).

Almost surely, 2^840043291 is an apocalyptic number.

840043291 is a deficient number, since it is larger than the sum of its proper divisors (1).

840043291 is an equidigital number, since it uses as much as digits as its factorization.

840043291 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 840043291 is about 28983.5003234599. The cubic root of 840043291 is about 943.5550048079. Note that the first 3 decimals are identical.

The spelling of 840043291 in words is "eight hundred forty million, forty-three thousand, two hundred ninety-one".