840834991 has 4 divisors (see below), whose sum is σ = 841137984. Its totient is φ = 840532000.

The previous prime is 840834947. The next prime is 840835031. The reversal of 840834991 is 199438048.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 840834991 - 2²⁵ = 807280559 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (840834931) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 147295 + ... + 152896.

It is an arithmetic number, because the mean of its divisors is an integer number (210284496).

Almost surely, 2^840834991 is an apocalyptic number.

840834991 is a deficient number, since it is larger than the sum of its proper divisors (302993).

840834991 is a wasteful number, since it uses less digits than its factorization.

840834991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 302992.

The product of its (nonzero) digits is 248832, while the sum is 46.

The square root of 840834991 is about 28997.1548776772. The cubic root of 840834991 is about 943.8513299909.

The spelling of 840834991 in words is "eight hundred forty million, eight hundred thirty-four thousand, nine hundred ninety-one".